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The main two issues were the timing out of operations due to wrong baudrate (2nd commit) and not finding the UART (3rd commit). Things work reasonably well with this, though I still occasionally see a timeout on the first command, necessitating a re-attach of the tty.

I still see the following error when attaching the tty:

 Bluetooth: hci0: BCM: failed to write update baudrate (-16)   (-EBUSY)

But it is benign, as the UART device does not appear to need its baud rate changed.

Finally, the 4th commit fixes the following two BUG's:

 BUG: sleeping function called from invalid context at kernel/locking/mutex.c
 in_atomic(): 1, irqs_disabled(): 0, pid: 7303, name: kworker/7:3
 INFO: lockdep is turned off.
 CPU: 7 PID: 7303 Comm: kworker/7:3 Tainted: G        W  OE   4.13.2+ #17
 Hardware name: Apple Inc. MacBookPro13,3/Mac-A5C67F76ED83108C, BIOS MBP133.8
 Workqueue: events hci_uart_write_work [hci_uart]
 Call Trace:
  dump_stack+0x8e/0xd6
  ___might_sleep+0x164/0x250
  __might_sleep+0x4a/0x80
  __mutex_lock+0x59/0xa00
  ? lock_acquire+0xa3/0x1f0
  ? lock_acquire+0xa3/0x1f0
  ? hci_uart_write_work+0xd3/0x160 [hci_uart]
  mutex_lock_nested+0x1b/0x20
  ? mutex_lock_nested+0x1b/0x20
  bcm_dequeue+0x21/0xc0 [hci_uart]
  hci_uart_write_work+0xe6/0x160 [hci_uart]
  process_one_work+0x253/0x6a0
  worker_thread+0x4d/0x3b0
  kthread+0x133/0x150
  ? process_one_work+0x6a0/0x6a0
  ? kthread_create_on_node+0x70/0x70
  ret_from_fork+0x2a/0x40

 BUG: sleeping function called from invalid context at kernel/locking/mutex.c
 in_atomic(): 1, irqs_disabled(): 0, pid: 13796, name: kworker/u16:2
 INFO: lockdep is turned off.
 CPU: 1 PID: 13796 Comm: kworker/u16:2 Tainted: G        W  OE   4.13.2+ #17
 Hardware name: Apple Inc. MacBookPro13,3/Mac-A5C67F76ED83108C, BIOS MBP133.8
 Workqueue: events_unbound flush_to_ldisc
 Call Trace:
  dump_stack+0x8e/0xd6
  ___might_sleep+0x164/0x250
  __might_sleep+0x4a/0x80
  __mutex_lock+0x59/0xa00
  ? trace_hardirqs_on+0xd/0x10
  ? hci_recv_frame+0x68/0xa0 [bluetooth]
  ? h4_recv_buf+0x17a/0x2f0 [hci_uart]
  mutex_lock_nested+0x1b/0x20
  ? mutex_lock_nested+0x1b/0x20
  bcm_recv+0x73/0x130 [hci_uart]
  hci_uart_tty_receive+0x61/0xa0 [hci_uart]
  tty_ldisc_receive_buf+0x48/0x50
  tty_port_default_receive_buf+0x49/0x70
  flush_to_ldisc+0x83/0xa0
  process_one_work+0x253/0x6a0
  worker_thread+0x4d/0x3b0
  kthread+0x133/0x150
  ? process_one_work+0x6a0/0x6a0
  ? kthread_create_on_node+0x70/0x70
  ret_from_fork+0x2a/0x40

The methods are supposed to return 0 on success, and the flag to enable
low-power operation was inverted.

Signed-off-by: Ronald Tschalär <[email protected]>
The device must be accessed via the configured baudrate for all
operations, or the operations will time out.

Note that currently bcm_set_baudrate() always fails (the commands always
return -EBUSY) and hence the operating baudrate is never actually set.
But if it were, it would need to be the same as the init baudrate, so
we keep setting oper_speed anyway.

Signed-off-by: Ronald Tschalär <[email protected]>
When the UART is part of an intel-lpss based mfd, the resulting device
tree has an extra level. Specifically we have the following layout (with
the /sys/devices/ prefix removed for brevity):

  ACPI device node:
    LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:94/BCM2E7C:00
  Associated physical device node:
    LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:94/BCM2E7C:00/physical_node -> pci0000:00/0000:00:1e.0/BCM2E7C:00/
  UART device node:
    pci0000:00/0000:00:1e.0/dw-apb-uart.2
  UART TTY device node:
    pci0000:00/0000:00:1e.0/dw-apb-uart.2/tty

This driver was assuming that physical device's parent is the UART, but
in this case the parent is the mfd device. We therefore check for both
cases.

Note that because this assumption appears in some user-space tools too,
it might be better to put the physical device node under the UART
instead of the mfd.

Signed-off-by: Ronald Tschalär <[email protected]>
Commit dec2c92 introduced locks around
the proto functions, using rwlock's, which do not allow sleeping while
the locks are held. However, the proto functions in hci_bcm use mutexes
and hence need to be able to sleep.

Therefore this replaces the rwlock's with rw_semaphore's. Because the
writes are very rare compared to the reads the percpu variant is used.

Lastly, the locks in the tx_wakeup callback needed to be removed because
that is called from an IRQ context. But since it doesn't actually call
any proto functions, instead just queueing work, and the
HCI_UART_PROTO_READY flag is checked (again) in the worker, this doesn't
cause any problems.

Signed-off-by: Ronald Tschalär <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Sep 24, 2017
commit 55acdd9 upstream.

Can be reproduced when running dlm_controld (tested on 4.4.x, 4.12.4):
 # seq 1 100 | xargs -P0 -n1 dlm_tool join
 # seq 1 100 | xargs -P0 -n1 dlm_tool leave

misc_register fails due to duplicate sysfs entry, which causes
dlm_device_register to free ls->ls_device.name.
In dlm_device_deregister the name was freed again, causing memory
corruption.

According to the comment in dlm_device_deregister the name should've been
set to NULL when registration fails,
so this patch does that.

sysfs: cannot create duplicate filename '/dev/char/10:1'
------------[ cut here ]------------
warning: cpu: 1 pid: 4450 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x56/0x70
modules linked in: msr rfcomm dlm ccm bnep dm_crypt uvcvideo
videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core videodev
btusb media btrtl btbcm btintel bluetooth ecdh_generic intel_rapl
x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm
snd_hda_codec_hdmi irqbypass crct10dif_pclmul crc32_pclmul
ghash_clmulni_intel thinkpad_acpi pcbc nvram snd_seq_midi
snd_seq_midi_event aesni_intel snd_hda_codec_realtek snd_hda_codec_generic
snd_rawmidi aes_x86_64 crypto_simd glue_helper snd_hda_intel snd_hda_codec
cryptd intel_cstate arc4 snd_hda_core snd_seq snd_seq_device snd_hwdep
iwldvm intel_rapl_perf mac80211 joydev input_leds iwlwifi serio_raw
cfg80211 snd_pcm shpchp snd_timer snd mac_hid mei_me lpc_ich mei soundcore
sunrpc parport_pc ppdev lp parport autofs4 i915 psmouse
 e1000e ahci libahci i2c_algo_bit sdhci_pci ptp drm_kms_helper sdhci
pps_core syscopyarea sysfillrect sysimgblt fb_sys_fops drm wmi video
cpu: 1 pid: 4450 comm: dlm_test.exe not tainted 4.12.4-041204-generic
hardware name: lenovo 232425u/232425u, bios g2et82ww (2.02 ) 09/11/2012
task: ffff96b0cbabe140 task.stack: ffffb199027d0000
rip: 0010:sysfs_warn_dup+0x56/0x70
rsp: 0018:ffffb199027d3c58 eflags: 00010282
rax: 0000000000000038 rbx: ffff96b0e2c49158 rcx: 0000000000000006
rdx: 0000000000000000 rsi: 0000000000000086 rdi: ffff96b15e24dcc0
rbp: ffffb199027d3c70 r08: 0000000000000001 r09: 0000000000000721
r10: ffffb199027d3c00 r11: 0000000000000721 r12: ffffb199027d3cd1
r13: ffff96b1592088f0 r14: 0000000000000001 r15: ffffffffffffffef
fs:  00007f78069c0700(0000) gs:ffff96b15e240000(0000)
knlgs:0000000000000000
cs:  0010 ds: 0000 es: 0000 cr0: 0000000080050033
cr2: 000000178625ed28 cr3: 0000000091d3e000 cr4: 00000000001406e0
call trace:
 sysfs_do_create_link_sd.isra.2+0x9e/0xb0
 sysfs_create_link+0x25/0x40
 device_add+0x5a9/0x640
 device_create_groups_vargs+0xe0/0xf0
 device_create_with_groups+0x3f/0x60
 ? snprintf+0x45/0x70
 misc_register+0x140/0x180
 device_write+0x6a8/0x790 [dlm]
 __vfs_write+0x37/0x160
 ? apparmor_file_permission+0x1a/0x20
 ? security_file_permission+0x3b/0xc0
 vfs_write+0xb5/0x1a0
 sys_write+0x55/0xc0
 ? sys_fcntl+0x5d/0xb0
 entry_syscall_64_fastpath+0x1e/0xa9
rip: 0033:0x7f78083454bd
rsp: 002b:00007f78069bbd30 eflags: 00000293 orig_rax: 0000000000000001
rax: ffffffffffffffda rbx: 0000000000000006 rcx: 00007f78083454bd
rdx: 000000000000009c rsi: 00007f78069bee00 rdi: 0000000000000005
rbp: 00007f77f8000a20 r08: 000000000000fcf0 r09: 0000000000000032
r10: 0000000000000024 r11: 0000000000000293 r12: 00007f78069bde00
r13: 00007f78069bee00 r14: 000000000000000a r15: 00007f78069bbd70
code: 85 c0 48 89 c3 74 12 b9 00 10 00 00 48 89 c2 31 f6 4c 89 ef e8 2c c8
ff ff 4c 89 e2 48 89 de 48 c7 c7 b0 8e 0c a8 e8 41 e8 ed ff <0f> ff 48 89
df e8 00 d5 f4 ff 5b 41 5c 41 5d 5d c3 66 0f 1f 84
---[ end trace 40412246357cc9e0 ]---

dlm: 59f24629-ae39-44e2-9030-397ebc2eda26: leaving the lockspace group...
bug: unable to handle kernel null pointer dereference at 0000000000000001
ip: [<ffffffff811a3b4a>] kmem_cache_alloc+0x7a/0x140
pgd 0
oops: 0000 [#1] smp
modules linked in: dlm 8021q garp mrp stp llc openvswitch nf_defrag_ipv6
nf_conntrack libcrc32c iptable_filter dm_multipath crc32_pclmul dm_mod
aesni_intel psmouse aes_x86_64 sg ablk_helper cryptd lrw gf128mul
glue_helper i2c_piix4 nls_utf8 tpm_tis tpm isofs nfsd auth_rpcgss
oid_registry nfs_acl lockd grace sunrpc xen_wdt ip_tables x_tables autofs4
hid_generic usbhid hid sr_mod cdrom sd_mod ata_generic pata_acpi 8139too
serio_raw ata_piix 8139cp mii uhci_hcd ehci_pci ehci_hcd libata
scsi_dh_rdac scsi_dh_hp_sw scsi_dh_emc scsi_dh_alua scsi_mod ipv6
cpu: 0 pid: 394 comm: systemd-udevd tainted: g w 4.4.0+0 #1
hardware name: xen hvm domu, bios 4.7.2-2.2 05/11/2017
task: ffff880002410000 ti: ffff88000243c000 task.ti: ffff88000243c000
rip: e030:[<ffffffff811a3b4a>] [<ffffffff811a3b4a>]
kmem_cache_alloc+0x7a/0x140
rsp: e02b:ffff88000243fd90 eflags: 00010202
rax: 0000000000000000 rbx: ffff8800029864d0 rcx: 000000000007b36c
rdx: 000000000007b36b rsi: 00000000024000c0 rdi: ffff880036801c00
rbp: ffff88000243fdc0 r08: 0000000000018880 r09: 0000000000000054
r10: 000000000000004a r11: ffff880034ace6c0 r12: 00000000024000c0
r13: ffff880036801c00 r14: 0000000000000001 r15: ffffffff8118dcc2
fs: 00007f0ab77548c0(0000) gs:ffff880036e00000(0000) knlgs:0000000000000000
cs: e033 ds: 0000 es: 0000 cr0: 0000000080050033
cr2: 0000000000000001 cr3: 000000000332d000 cr4: 0000000000040660
stack:
ffffffff8118dc90 ffff8800029864d0 0000000000000000 ffff88003430b0b0
ffff880034b78320 ffff88003430b0b0 ffff88000243fdf8 ffffffff8118dcc2
ffff8800349c6700 ffff8800029864d0 000000000000000b 00007f0ab7754b90
call trace:
[<ffffffff8118dc90>] ? anon_vma_fork+0x60/0x140
[<ffffffff8118dcc2>] anon_vma_fork+0x92/0x140
[<ffffffff8107033e>] copy_process+0xcae/0x1a80
[<ffffffff8107128b>] _do_fork+0x8b/0x2d0
[<ffffffff81071579>] sys_clone+0x19/0x20
[<ffffffff815a30ae>] entry_syscall_64_fastpath+0x12/0x71
] code: f6 75 1c 4c 89 fa 44 89 e6 4c 89 ef e8 a7 e4 00 00 41 f7 c4 00 80
00 00 49 89 c6 74 47 eb 32 49 63 45 20 48 8d 4a 01 4d 8b 45 00 <49> 8b 1c
06 4c 89 f0 65 49 0f c7 08 0f 94 c0 84 c0 74 ac 49 63
rip [<ffffffff811a3b4a>] kmem_cache_alloc+0x7a/0x140
rsp <ffff88000243fd90>
cr2: 0000000000000001
--[ end trace 70cb9fd1b164a0e8 ]--

Signed-off-by: Edwin Török <[email protected]>
Signed-off-by: David Teigland <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
@l1k
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l1k commented Sep 25, 2017

Great job @roadrunner2!

As to the first commit, the schematics of the MB8,1 call the line BT_LOW_PWR_L, so it's active low apparently. And BTLP(1) sets the output value to 0. Hence I'm surprised that the value needs to be inverted. What's the behavior without this change, does it not work or consume more power?

D'accord on the botched ACPI_SUCCESS() check.

The occasional timeout on the first command sounds like a delay may be needed in bcm_apple_set_power() and/or bcm_apple_set_device_wake(). However looking at IOBluetoothHostControllerUARTTransport.kext in the disassembler I notice that it doesn't wait after calling the ACPI methods, it just carries on immediately. Still might be worth a try.

As to the second commit, could you check where the -EBUSY is coming from? In __hci_cmd_sync_ev(), I suppose hdev->req_status == HCI_REQ_DONE, so the -EBUSY is coming directly from the device, right? If you change the if (speed > 3000000) check to >=, do you still get the same error? If you do, maybe the device refuses to set the baudrate and the meaning of the baud device property is thus that it is a fixed speed that cannot be changed.

The other two commits I need to take a closer look.

@roadrunner2
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@l1k Regarding the schematics etc, that looks correct: BTLP(1) puts the device into low power - see also the DSDT snippet I posted. The issue is that bcm_apple_set_device_wake() gets called with enable false when going to sleep, and with enable true when waking up. Ergo enable == false => BLTP(1) and enable == true => BLTP(0). Unless I'm totally confused.

In any case I haven't actually tested suspend and resume yet - I just noticed the issue while looking at the code.

Regarding EBUSY: I already tried adding up to 100ms delay after power up, but that didn't help. And I traced the EBUSY down to getting the bluetooth status code 0x0c (which gets translated to EBUSY by bt_to_errno()) in hci_req_cmd_complete(), called either by hci_cmd_complete_evt() or hci_cmd_status_evt(). I'll try to trace it further back in a few days.

@l1k
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l1k commented Oct 7, 2017

The issue is that bcm_apple_set_device_wake() gets called with enable false when going to sleep, and with enable true when waking up. Ergo enable == false => BLTP(1) and enable == true => BLTP(0). Unless I'm totally confused.

Okay, thanks for the explanation. Apparently the inverse polarity of the pin is open coded in this driver, which is crap, normally this is declared in the platform firmware.

Anyway, the hci_bcm driver is being migrated to the new serial device bus, i.e. there is no tty chardev anymore for the UART, invocation of hciattach is no longer necessary and the kernel automatically switches to N_HCI ldisc and probes the hci_bcm driver. This also solves the issue addressed by your third patch in this pull. An initial set of 9 patches by Hans de Goede was merged to bluetooth-next a day ago and there are 2 other patches needed by Frédéric Danis which are unmerged yet but are slated for merging via the ACPI subsystem. Johan Hovold came up with a few comments and objections today but nothing that can't be resolved. I'm in the process of rebasing onto these patches, actually I've just done that but I need to review and refine a little further and will likely push the new branch on Monday. Thanks for your patience.

@l1k
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l1k commented Oct 9, 2017

So I've pushed the hci_bcm_v1 branch today as an initial attempt to rebase on current bluetooth-next. Compile-tested only as I don't have the hardware. Be sure to enable CONFIG_SERIAL_DEV_BUS, CONFIG_SERIAL_DEV_CTRL_TTYPORT and CONFIG_BT_HCIUART_SERDEV to test this. Note that bcm_probe() is dead code now, only bcm_serdev_probe() is relevant.

@l1k
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l1k commented Oct 10, 2017

Frédéric Danis posted a v2 of his patches so I rebased the hci_bcm_v1 branch on top of them. Sorry, we're shooting at a moving target here.

@l1k
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l1k commented Oct 11, 2017

Another day, another rebase. This is now based on Frédéric Danis' v3 plus a fix by Johan Hovold, all on top of current bluetooth-next.

@roadrunner2
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😃 I'll give it a whirl in the next couple days.

One thing I was wondering: should the proto-locks patch be pushed for 4.14? I honestly don't see how this can be working at all, unless nobody is using hci_bcm or I'm missing something basic.

roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
…() returns

The cgroup_taskset structure within the larger cgroup_mgctx structure
is supposed to be used once and then discarded. That is not really the
case in the hotplug code path:

cpuset_hotplug_workfn()
 - cgroup_transfer_tasks()
   - cgroup_migrate()
     - cgroup_migrate_add_task()
     - cgroup_migrate_execute()

In this case, the cgroup_migrate() function is called multiple time
with the same cgroup_mgctx structure to transfer the tasks from
one cgroup to another one-by-one. The second time cgroup_migrate()
is called, the cgroup_taskset will be in an incorrect state and so
may cause the system to panic. For example,

  [  150.888410] Faulting instruction address: 0xc0000000001db648
  [  150.888414] Oops: Kernel access of bad area, sig: 11 [#1]
  [  150.888417] SMP NR_CPUS=2048
  [  150.888417] NUMA
  [  150.888419] pSeries
    :
  [  150.888545] NIP [c0000000001db648] cpuset_can_attach+0x58/0x1b0
  [  150.888548] LR [c0000000001db638] cpuset_can_attach+0x48/0x1b0
  [  150.888551] Call Trace:
  [  150.888554] [c0000005f65cb940] [c0000000001db638] cpuset_can_attach+0x48/0x1b 0 (unreliable)
  [  150.888559] [c0000005f65cb9a0] [c0000000001cff04] cgroup_migrate_execute+0xc4/0x4b0
  [  150.888563] [c0000005f65cba20] [c0000000001d7d14] cgroup_transfer_tasks+0x1d4/0x370
  [  150.888568] [c0000005f65cbb70] [c0000000001ddcb0] cpuset_hotplug_workfn+0x710/0x8f0
  [  150.888572] [c0000005f65cbc80] [c00000000012032c] process_one_work+0x1ac/0x4d0
  [  150.888576] [c0000005f65cbd20] [c0000000001206f8] worker_thread+0xa8/0x5b0
  [  150.888580] [c0000005f65cbdc0] [c0000000001293f8] kthread+0x168/0x1b0
  [  150.888584] [c0000005f65cbe30] [c00000000000b368] ret_from_kernel_thread+0x5c/0x74

To allow reuse of the cgroup_mgctx structure, some fields in that
structure are now re-initialized at the end of cgroup_migrate_execute()
function call so that the structure can be reused again in a later
iteration without causing problem.

This bug was introduced in the commit e595cd7 ("group: track
migration context in cgroup_mgctx") in 4.11. This commit moves the
cgroup_taskset initialization out of cgroup_migrate(). The commit
10467270fb3 ("cgroup: don't call migration methods if there are no
tasks to migrate") helped, but did not completely resolve the problem.

Fixes: e595cd7 ("group: track migration context in cgroup_mgctx")
Signed-off-by: Waiman Long <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
Cc: [email protected] # v4.11+
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
Xiaolong reported a suspicious rcu_dereference_check in the device
unregister notifier callback. Since we do not dereference the
rx_handler_data, it's ok to just check for the value of the pointer.
Note that this section is already protected by rtnl_lock.

[  101.364846] WARNING: suspicious RCU usage
[  101.365654] 4.13.0-rc6-01701-gceed73a #1 Not tainted
[  101.370873] -----------------------------
[  101.372472] drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c:57 suspicious rcu_dereference_check() usage!
[  101.374427]
[  101.374427] other info that might help us debug this:
[  101.374427]
[  101.387491]
[  101.387491] rcu_scheduler_active = 2, debug_locks = 1
[  101.389368] 1 lock held by trinity-main/2809:
[  101.390736]  #0:  (rtnl_mutex){+.+.+.}, at: [<8146085b>] rtnl_lock+0xf/0x11
[  101.395482]
[  101.395482] stack backtrace:
[  101.396948] CPU: 0 PID: 2809 Comm: trinity-main Not tainted 4.13.0-rc6-01701-gceed73a #1
[  101.398857] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.3-20161025_171302-gandalf 04/01/2014
[  101.401079] Call Trace:
[  101.401656]  dump_stack+0xa1/0xeb
[  101.402871]  lockdep_rcu_suspicious+0xc7/0xd0
[  101.403665]  rmnet_is_real_dev_registered+0x40/0x4e
[  101.405199]  rmnet_config_notify_cb+0x2c/0x142
[  101.406344]  ? wireless_nlevent_flush+0x47/0x71
[  101.407385]  notifier_call_chain+0x2d/0x47
[  101.408645]  raw_notifier_call_chain+0xc/0xe
[  101.409882]  call_netdevice_notifiers_info+0x41/0x49
[  101.411402]  call_netdevice_notifiers+0xc/0xe
[  101.412713]  rollback_registered_many+0x268/0x36e
[  101.413702]  rollback_registered+0x39/0x56
[  101.414965]  unregister_netdevice_queue+0x79/0x88
[  101.415908]  unregister_netdev+0x16/0x1d

Fixes: ceed73a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Signed-off-by: Subash Abhinov Kasiviswanathan <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
The driver calls spi_get_drvdata() in its ->remove hook even though it
has never called spi_set_drvdata().  Stack trace for posterity:

Unable to handle kernel NULL pointer dereference at virtual address 00000220
Internal error: Oops: 5 [#1] SMP ARM
[<8072f564>] (mutex_lock) from [<7f1400d0>] (iio_device_unregister+0x24/0x7c [industrialio])
[<7f1400d0>] (iio_device_unregister [industrialio]) from [<7f15e020>] (mcp320x_remove+0x20/0x30 [mcp320x])
[<7f15e020>] (mcp320x_remove [mcp320x]) from [<8055a8cc>] (spi_drv_remove+0x2c/0x44)
[<8055a8cc>] (spi_drv_remove) from [<805087bc>] (__device_release_driver+0x98/0x134)
[<805087bc>] (__device_release_driver) from [<80509180>] (driver_detach+0xdc/0xe0)
[<80509180>] (driver_detach) from [<8050823c>] (bus_remove_driver+0x5c/0xb0)
[<8050823c>] (bus_remove_driver) from [<80509ab0>] (driver_unregister+0x38/0x58)
[<80509ab0>] (driver_unregister) from [<7f15e69c>] (mcp320x_driver_exit+0x14/0x1c [mcp320x])
[<7f15e69c>] (mcp320x_driver_exit [mcp320x]) from [<801a78d0>] (SyS_delete_module+0x184/0x1d0)
[<801a78d0>] (SyS_delete_module) from [<80108100>] (ret_fast_syscall+0x0/0x1c)

Fixes: f5ce4a7 ("iio: adc: add driver for MCP3204/08 12-bit ADC")
Cc: Oskar Andero <[email protected]>
Signed-off-by: Lukas Wunner <[email protected]>
Cc: <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
Because keyctl_read_key() looks up the key with no permissions
requested, it may find a negatively instantiated key.  If the key is
also possessed, we went ahead and called ->read() on the key.  But the
key payload will actually contain the ->reject_error rather than the
normal payload.  Thus, the kernel oopses trying to read the
user_key_payload from memory address (int)-ENOKEY = 0x00000000ffffff82.

Fortunately the payload data is stored inline, so it shouldn't be
possible to abuse this as an arbitrary memory read primitive...

Reproducer:
    keyctl new_session
    keyctl request2 user desc '' @s
    keyctl read $(keyctl show | awk '/user: desc/ {print $1}')

It causes a crash like the following:
     BUG: unable to handle kernel paging request at 00000000ffffff92
     IP: user_read+0x33/0xa0
     PGD 36a54067 P4D 36a54067 PUD 0
     Oops: 0000 [#1] SMP
     CPU: 0 PID: 211 Comm: keyctl Not tainted 4.14.0-rc1 torvalds#337
     Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
     task: ffff90aa3b74c3c0 task.stack: ffff9878c0478000
     RIP: 0010:user_read+0x33/0xa0
     RSP: 0018:ffff9878c047bee8 EFLAGS: 00010246
     RAX: 0000000000000001 RBX: ffff90aa3d7da340 RCX: 0000000000000017
     RDX: 0000000000000000 RSI: 00000000ffffff82 RDI: ffff90aa3d7da340
     RBP: ffff9878c047bf00 R08: 00000024f95da94f R09: 0000000000000000
     R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
     R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
     FS:  00007f58ece69740(0000) GS:ffff90aa3e200000(0000) knlGS:0000000000000000
     CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
     CR2: 00000000ffffff92 CR3: 0000000036adc001 CR4: 00000000003606f0
     Call Trace:
      keyctl_read_key+0xac/0xe0
      SyS_keyctl+0x99/0x120
      entry_SYSCALL_64_fastpath+0x1f/0xbe
     RIP: 0033:0x7f58ec787bb9
     RSP: 002b:00007ffc8d401678 EFLAGS: 00000206 ORIG_RAX: 00000000000000fa
     RAX: ffffffffffffffda RBX: 00007ffc8d402800 RCX: 00007f58ec787bb9
     RDX: 0000000000000000 RSI: 00000000174a63ac RDI: 000000000000000b
     RBP: 0000000000000004 R08: 00007ffc8d402809 R09: 0000000000000020
     R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffc8d402800
     R13: 00007ffc8d4016e0 R14: 0000000000000000 R15: 0000000000000000
     Code: e5 41 55 49 89 f5 41 54 49 89 d4 53 48 89 fb e8 a4 b4 ad ff 85 c0 74 09 80 3d b9 4c 96 00 00 74 43 48 8b b3 20 01 00 00 4d 85 ed <0f> b7 5e 10 74 29 4d 85 e4 74 24 4c 39 e3 4c 89 e2 4c 89 ef 48
     RIP: user_read+0x33/0xa0 RSP: ffff9878c047bee8
     CR2: 00000000ffffff92

Fixes: 61ea0c0 ("KEYS: Skip key state checks when checking for possession")
Cc: <[email protected]>	[v3.13+]
Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: David Howells <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
…rse nlmsg properly

ChunYu found a kernel crash by syzkaller:

[  651.617875] kasan: CONFIG_KASAN_INLINE enabled
[  651.618217] kasan: GPF could be caused by NULL-ptr deref or user memory access
[  651.618731] general protection fault: 0000 [#1] SMP KASAN
[  651.621543] CPU: 1 PID: 9539 Comm: scsi Not tainted 4.11.0.cov torvalds#32
[  651.621938] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[  651.622309] task: ffff880117780000 task.stack: ffff8800a3188000
[  651.622762] RIP: 0010:skb_release_data+0x26c/0x590
[...]
[  651.627260] Call Trace:
[  651.629156]  skb_release_all+0x4f/0x60
[  651.629450]  consume_skb+0x1a5/0x600
[  651.630705]  netlink_unicast+0x505/0x720
[  651.632345]  netlink_sendmsg+0xab2/0xe70
[  651.633704]  sock_sendmsg+0xcf/0x110
[  651.633942]  ___sys_sendmsg+0x833/0x980
[  651.637117]  __sys_sendmsg+0xf3/0x240
[  651.638820]  SyS_sendmsg+0x32/0x50
[  651.639048]  entry_SYSCALL_64_fastpath+0x1f/0xc2

It's caused by skb_shared_info at the end of sk_buff was overwritten by
ISCSI_KEVENT_IF_ERROR when parsing nlmsg info from skb in iscsi_if_rx.

During the loop if skb->len == nlh->nlmsg_len and both are sizeof(*nlh),
ev = nlmsg_data(nlh) will acutally get skb_shinfo(SKB) instead and set a
new value to skb_shinfo(SKB)->nr_frags by ev->type.

This patch is to fix it by checking nlh->nlmsg_len properly there to
avoid over accessing sk_buff.

Reported-by: ChunYu Wang <[email protected]>
Signed-off-by: Xin Long <[email protected]>
Acked-by: Chris Leech <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
Guillaume Nault says:

====================
l2tp: fix some races in session deletion

L2TP provides several interfaces for deleting sessions. Using two of
them concurrently can lead to use-after-free bugs.

Patch l1k#2 uses a flag to prevent double removal of L2TP sessions.
Patch #1 fixes a bug found in the way. Fixing this bug is also
necessary for patch l1k#2 to handle all cases.

This issue is similar to the tunnel deletion bug being worked on by
Sabrina: https://patchwork.ozlabs.org/patch/814173/
====================

Signed-off-by: David S. Miller <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
ti-cpufreq and cpufreq-dt-platdev drivers are registering platform-device
with same name "cpufreq-dt" using platform_device_register_*() routines.
This is leading to build warnings appended below.

Providing hardware information to OPP framework along with the platform-
device creation should be done by ti-cpufreq driver before cpufreq-dt
driver comes into place.

This patch add's TI am33xx, am43 and dra7 platforms (which use opp-v2
property) to the blacklist of devices in cpufreq-dt-platform driver to
avoid creating platform-device twice and remove build warnings.

[    2.370167] ------------[ cut here ]------------
[    2.375087] WARNING: CPU: 0 PID: 1 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x58/0x78
[    2.383112] sysfs: cannot create duplicate filename '/devices/platform/cpufreq-dt'
[    2.391219] Modules linked in:
[    2.394506] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.13.0-next-20170912 #1
[    2.402006] Hardware name: Generic AM33XX (Flattened Device Tree)
[    2.408437] [<c0110a28>] (unwind_backtrace) from [<c010ca84>] (show_stack+0x10/0x14)
[    2.416568] [<c010ca84>] (show_stack) from [<c0827d64>] (dump_stack+0xac/0xe0)
[    2.424165] [<c0827d64>] (dump_stack) from [<c0137470>] (__warn+0xd8/0x104)
[    2.431488] [<c0137470>] (__warn) from [<c01374d0>] (warn_slowpath_fmt+0x34/0x44)
[    2.439351] [<c01374d0>] (warn_slowpath_fmt) from [<c03459d0>] (sysfs_warn_dup+0x58/0x78)
[    2.447938] [<c03459d0>] (sysfs_warn_dup) from [<c0345ab8>] (sysfs_create_dir_ns+0x80/0x98)
[    2.456719] [<c0345ab8>] (sysfs_create_dir_ns) from [<c082c554>] (kobject_add_internal+0x9c/0x2d4)
[    2.466124] [<c082c554>] (kobject_add_internal) from [<c082c7d8>] (kobject_add+0x4c/0x9c)
[    2.474712] [<c082c7d8>] (kobject_add) from [<c05803e4>] (device_add+0xcc/0x57c)
[    2.482489] [<c05803e4>] (device_add) from [<c0584b74>] (platform_device_add+0x100/0x220)
[    2.491085] [<c0584b74>] (platform_device_add) from [<c05855a8>] (platform_device_register_full+0xf4/0x118)
[    2.501305] [<c05855a8>] (platform_device_register_full) from [<c067023c>] (ti_cpufreq_init+0x150/0x22c)
[    2.511253] [<c067023c>] (ti_cpufreq_init) from [<c0101df4>] (do_one_initcall+0x3c/0x170)
[    2.519838] [<c0101df4>] (do_one_initcall) from [<c0c00eb4>] (kernel_init_freeable+0x1fc/0x2c4)
[    2.528974] [<c0c00eb4>] (kernel_init_freeable) from [<c083bcac>] (kernel_init+0x8/0x110)
[    2.537565] [<c083bcac>] (kernel_init) from [<c0107d18>] (ret_from_fork+0x14/0x3c)
[    2.545981] ---[ end trace 2fc00e213c13ab20 ]---
[    2.551051] ------------[ cut here ]------------
[    2.555931] WARNING: CPU: 0 PID: 1 at lib/kobject.c:240 kobject_add_internal+0x254/0x2d4
[    2.564578] kobject_add_internal failed for cpufreq-dt with -EEXIST, don't try to register
things with the same name in the same directory.
[    2.577977] Modules linked in:
[    2.581261] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G        W       4.13.0-next-20170912 #1
[    2.590013] Hardware name: Generic AM33XX (Flattened Device Tree)
[    2.596437] [<c0110a28>] (unwind_backtrace) from [<c010ca84>] (show_stack+0x10/0x14)
[    2.604573] [<c010ca84>] (show_stack) from [<c0827d64>] (dump_stack+0xac/0xe0)
[    2.612172] [<c0827d64>] (dump_stack) from [<c0137470>] (__warn+0xd8/0x104)
[    2.619494] [<c0137470>] (__warn) from [<c01374d0>] (warn_slowpath_fmt+0x34/0x44)
[    2.627362] [<c01374d0>] (warn_slowpath_fmt) from [<c082c70c>] (kobject_add_internal+0x254/0x2d4)
[    2.636666] [<c082c70c>] (kobject_add_internal) from [<c082c7d8>] (kobject_add+0x4c/0x9c)
[    2.645255] [<c082c7d8>] (kobject_add) from [<c05803e4>] (device_add+0xcc/0x57c)
[    2.653027] [<c05803e4>] (device_add) from [<c0584b74>] (platform_device_add+0x100/0x220)
[    2.661615] [<c0584b74>] (platform_device_add) from [<c05855a8>] (platform_device_register_full+0xf4/0x118)
[    2.671833] [<c05855a8>] (platform_device_register_full) from [<c067023c>] (ti_cpufreq_init+0x150/0x22c)
[    2.681779] [<c067023c>] (ti_cpufreq_init) from [<c0101df4>] (do_one_initcall+0x3c/0x170)
[    2.690377] [<c0101df4>] (do_one_initcall) from [<c0c00eb4>] (kernel_init_freeable+0x1fc/0x2c4)
[    2.699510] [<c0c00eb4>] (kernel_init_freeable) from [<c083bcac>] (kernel_init+0x8/0x110)
[    2.708106] [<c083bcac>] (kernel_init) from [<c0107d18>] (ret_from_fork+0x14/0x3c)
[    2.716217] ---[ end trace 2fc00e213c13ab21 ]---

Fixes: edeec42 (cpufreq: dt-cpufreq: platdev Automatically create device with OPP v2)
Signed-off-by: Suniel Mahesh <[email protected]>
Acked-by: Viresh Kumar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
The ARM short descriptor has already limited the physical address
to 32bit after the commit <76557391433c> ("iommu/io-pgtable: Sanitise
map/unmap addresses"). But in MediaTek 4GB mode, the physical address
is from 0x1_0000_0000 to 0x1_ffff_ffff. this will cause:

WARNING: CPU: 4 PID: 3900 at
xxx/drivers/iommu/io-pgtable-arm-v7s.c:482 arm_v7s_map+0x40/0xf8
Modules linked in:

CPU: 4 PID: 3900 Comm: weston Tainted: G S      W       4.9.44 #1
Hardware name: MediaTek MT2712m1v1 board (DT)
task: ffffffc0eaa5b280 task.stack: ffffffc0e9858000
PC is at arm_v7s_map+0x40/0xf8
LR is at mtk_iommu_map+0x64/0x90
pc : [<ffffff80085b09e8>] lr : [<ffffff80085b29fc>] pstate: 000001c5
sp : ffffffc0e985b920
x29: ffffffc0e985b920 x28: 0000000127d00000
x27: 0000000000100000 x26: ffffff8008f9e000
x25: 0000000000000003 x24: 0000000000100000
x23: 0000000127d00000 x22: 00000000ff800000
x21: ffffffc0f7ec8ce0 x20: 0000000000000003
x19: 0000000000000003 x18: 0000000000000002
x17: 0000007f7e5d72c0 x16: ffffff80082b0f08
x15: 0000000000000001 x14: 000000000000003f
x13: 0000000000000000 x12: 0000000000000028
x11: 0088000000000000 x10: 0000000000000000
x9 : ffffff80092fa000 x8 : ffffffc0e9858000
x7 : ffffff80085b29d8 x6 : 0000000000000000
x5 : ffffff80085b09a8 x4 : 0000000000000003
x3 : 0000000000100000 x2 : 0000000127d00000
x1 : 00000000ff800000 x0 : 0000000000000001
...
Call trace:
[<ffffff80085b09e8>] arm_v7s_map+0x40/0xf8
[<ffffff80085b29fc>] mtk_iommu_map+0x64/0x90
[<ffffff80085ab5f8>] iommu_map+0x100/0x3a0
[<ffffff80085ab99c>] default_iommu_map_sg+0x104/0x168
[<ffffff80085aead8>] iommu_dma_alloc+0x238/0x3f8
[<ffffff8008098b30>] __iommu_alloc_attrs+0xa8/0x260
[<ffffff80085f364c>] mtk_drm_gem_create+0xac/0x180
[<ffffff80085f3894>] mtk_drm_gem_dumb_create+0x54/0xc8
[<ffffff80085d576c>] drm_mode_create_dumb_ioctl+0xa4/0xd8
[<ffffff80085cb2a0>] drm_ioctl+0x1c0/0x490

In order to satify this, Limit the physical address to 32bit.

Signed-off-by: Yong Wu <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Joerg Roedel <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
…ping

When bootup a PVM guest with large memory(Ex.240GB), XEN provided initial
mapping overlaps with kernel module virtual space. When mapping in this space
is cleared by xen_cleanhighmap(), in certain case there could be an 2MB mapping
left. This is due to XEN initialize 4MB aligned mapping but xen_cleanhighmap()
finish at 2MB boundary.

When module loading is just on top of the 2MB space, got below warning:

WARNING: at mm/vmalloc.c:106 vmap_pte_range+0x14e/0x190()
Call Trace:
 [<ffffffff81117083>] warn_alloc_failed+0xf3/0x160
 [<ffffffff81146022>] __vmalloc_area_node+0x182/0x1c0
 [<ffffffff810ac91e>] ? module_alloc_update_bounds+0x1e/0x80
 [<ffffffff81145df7>] __vmalloc_node_range+0xa7/0x110
 [<ffffffff810ac91e>] ? module_alloc_update_bounds+0x1e/0x80
 [<ffffffff8103ca54>] module_alloc+0x64/0x70
 [<ffffffff810ac91e>] ? module_alloc_update_bounds+0x1e/0x80
 [<ffffffff810ac91e>] module_alloc_update_bounds+0x1e/0x80
 [<ffffffff810ac9a7>] move_module+0x27/0x150
 [<ffffffff810aefa0>] layout_and_allocate+0x120/0x1b0
 [<ffffffff810af0a8>] load_module+0x78/0x640
 [<ffffffff811ff90b>] ? security_file_permission+0x8b/0x90
 [<ffffffff810af6d2>] sys_init_module+0x62/0x1e0
 [<ffffffff815154c2>] system_call_fastpath+0x16/0x1b

Then the mapping of 2MB is cleared, finally oops when the page in that space is
accessed.

BUG: unable to handle kernel paging request at ffff880022600000
IP: [<ffffffff81260877>] clear_page_c_e+0x7/0x10
PGD 1788067 PUD 178c067 PMD 22434067 PTE 0
Oops: 0002 [#1] SMP
Call Trace:
 [<ffffffff81116ef7>] ? prep_new_page+0x127/0x1c0
 [<ffffffff81117d42>] get_page_from_freelist+0x1e2/0x550
 [<ffffffff81133010>] ? ii_iovec_copy_to_user+0x90/0x140
 [<ffffffff81119c9d>] __alloc_pages_nodemask+0x12d/0x230
 [<ffffffff81155516>] alloc_pages_vma+0xc6/0x1a0
 [<ffffffff81006ffd>] ? pte_mfn_to_pfn+0x7d/0x100
 [<ffffffff81134cfb>] do_anonymous_page+0x16b/0x350
 [<ffffffff81139c34>] handle_pte_fault+0x1e4/0x200
 [<ffffffff8100712e>] ? xen_pmd_val+0xe/0x10
 [<ffffffff810052c9>] ? __raw_callee_save_xen_pmd_val+0x11/0x1e
 [<ffffffff81139dab>] handle_mm_fault+0x15b/0x270
 [<ffffffff81510c10>] do_page_fault+0x140/0x470
 [<ffffffff8150d7d5>] page_fault+0x25/0x30

Call xen_cleanhighmap() with 4MB aligned for page tables mapping to fix it.
The unnecessory call of xen_cleanhighmap() in DEBUG mode is also removed.

-v2: add comment about XEN alignment from Juergen.

References: https://lists.xen.org/archives/html/xen-devel/2012-07/msg01562.html
Signed-off-by: Zhenzhong Duan <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>

[boris: added 'xen/mmu' tag to commit subject]
Signed-off-by: Boris Ostrovsky <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
We currently route pte translation faults via do_page_fault, which elides
the address check against TASK_SIZE before invoking the mm fault handling
code. However, this can cause issues with the path walking code in
conjunction with our word-at-a-time implementation because
load_unaligned_zeropad can end up faulting in kernel space if it reads
across a page boundary and runs into a page fault (e.g. by attempting to
read from a guard region).

In the case of such a fault, load_unaligned_zeropad has registered a
fixup to shift the valid data and pad with zeroes, however the abort is
reported as a level 3 translation fault and we dispatch it straight to
do_page_fault, despite it being a kernel address. This results in calling
a sleeping function from atomic context:

  BUG: sleeping function called from invalid context at arch/arm64/mm/fault.c:313
  in_atomic(): 0, irqs_disabled(): 0, pid: 10290
  Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
  [...]
  [<ffffff8e016cd0cc>] ___might_sleep+0x134/0x144
  [<ffffff8e016cd158>] __might_sleep+0x7c/0x8c
  [<ffffff8e016977f0>] do_page_fault+0x140/0x330
  [<ffffff8e01681328>] do_mem_abort+0x54/0xb0
  Exception stack(0xfffffffb20247a70 to 0xfffffffb20247ba0)
  [...]
  [<ffffff8e016844fc>] el1_da+0x18/0x78
  [<ffffff8e017f399c>] path_parentat+0x44/0x88
  [<ffffff8e017f4c9c>] filename_parentat+0x5c/0xd8
  [<ffffff8e017f5044>] filename_create+0x4c/0x128
  [<ffffff8e017f59e4>] SyS_mkdirat+0x50/0xc8
  [<ffffff8e01684e30>] el0_svc_naked+0x24/0x28
  Code: 36380080 d5384100 f9400800 9402566d (d4210000)
  ---[ end trace 2d01889f2bca9b9f ]---

Fix this by dispatching all translation faults to do_translation_faults,
which avoids invoking the page fault logic for faults on kernel addresses.

Cc: <[email protected]>
Reported-by: Ankit Jain <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
The following lockdep splat has been noticed during LTP testing

  ======================================================
  WARNING: possible circular locking dependency detected
  4.13.0-rc3-next-20170807 torvalds#12 Not tainted
  ------------------------------------------------------
  a.out/4771 is trying to acquire lock:
   (cpu_hotplug_lock.rw_sem){++++++}, at: [<ffffffff812b4668>] drain_all_stock.part.35+0x18/0x140

  but task is already holding lock:
   (&mm->mmap_sem){++++++}, at: [<ffffffff8106eb35>] __do_page_fault+0x175/0x530

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> l1k#3 (&mm->mmap_sem){++++++}:
         lock_acquire+0xc9/0x230
         __might_fault+0x70/0xa0
         _copy_to_user+0x23/0x70
         filldir+0xa7/0x110
         xfs_dir2_sf_getdents.isra.10+0x20c/0x2c0 [xfs]
         xfs_readdir+0x1fa/0x2c0 [xfs]
         xfs_file_readdir+0x30/0x40 [xfs]
         iterate_dir+0x17a/0x1a0
         SyS_getdents+0xb0/0x160
         entry_SYSCALL_64_fastpath+0x1f/0xbe

  -> l1k#2 (&type->i_mutex_dir_key#3){++++++}:
         lock_acquire+0xc9/0x230
         down_read+0x51/0xb0
         lookup_slow+0xde/0x210
         walk_component+0x160/0x250
         link_path_walk+0x1a6/0x610
         path_openat+0xe4/0xd50
         do_filp_open+0x91/0x100
         file_open_name+0xf5/0x130
         filp_open+0x33/0x50
         kernel_read_file_from_path+0x39/0x80
         _request_firmware+0x39f/0x880
         request_firmware_direct+0x37/0x50
         request_microcode_fw+0x64/0xe0
         reload_store+0xf7/0x180
         dev_attr_store+0x18/0x30
         sysfs_kf_write+0x44/0x60
         kernfs_fop_write+0x113/0x1a0
         __vfs_write+0x37/0x170
         vfs_write+0xc7/0x1c0
         SyS_write+0x58/0xc0
         do_syscall_64+0x6c/0x1f0
         return_from_SYSCALL_64+0x0/0x7a

  -> #1 (microcode_mutex){+.+.+.}:
         lock_acquire+0xc9/0x230
         __mutex_lock+0x88/0x960
         mutex_lock_nested+0x1b/0x20
         microcode_init+0xbb/0x208
         do_one_initcall+0x51/0x1a9
         kernel_init_freeable+0x208/0x2a7
         kernel_init+0xe/0x104
         ret_from_fork+0x2a/0x40

  -> #0 (cpu_hotplug_lock.rw_sem){++++++}:
         __lock_acquire+0x153c/0x1550
         lock_acquire+0xc9/0x230
         cpus_read_lock+0x4b/0x90
         drain_all_stock.part.35+0x18/0x140
         try_charge+0x3ab/0x6e0
         mem_cgroup_try_charge+0x7f/0x2c0
         shmem_getpage_gfp+0x25f/0x1050
         shmem_fault+0x96/0x200
         __do_fault+0x1e/0xa0
         __handle_mm_fault+0x9c3/0xe00
         handle_mm_fault+0x16e/0x380
         __do_page_fault+0x24a/0x530
         do_page_fault+0x30/0x80
         page_fault+0x28/0x30

  other info that might help us debug this:

  Chain exists of:
    cpu_hotplug_lock.rw_sem --> &type->i_mutex_dir_key#3 --> &mm->mmap_sem

   Possible unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(&mm->mmap_sem);
                                 lock(&type->i_mutex_dir_key#3);
                                 lock(&mm->mmap_sem);
    lock(cpu_hotplug_lock.rw_sem);

   *** DEADLOCK ***

  2 locks held by a.out/4771:
   #0:  (&mm->mmap_sem){++++++}, at: [<ffffffff8106eb35>] __do_page_fault+0x175/0x530
   #1:  (percpu_charge_mutex){+.+...}, at: [<ffffffff812b4c97>] try_charge+0x397/0x6e0

The problem is very similar to the one fixed by commit a459eeb
("mm, page_alloc: do not depend on cpu hotplug locks inside the
allocator").  We are taking hotplug locks while we can be sitting on top
of basically arbitrary locks.  This just calls for problems.

We can get rid of {get,put}_online_cpus, fortunately.  We do not have to
be worried about races with memory hotplug because drain_local_stock,
which is called from both the WQ draining and the memory hotplug
contexts, is always operating on the local cpu stock with IRQs disabled.

The only thing to be careful about is that the target memcg doesn't
vanish while we are still in drain_all_stock so take a reference on it.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Michal Hocko <[email protected]>
Reported-by: Artem Savkov <[email protected]>
Tested-by: Artem Savkov <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
printk_ratelimit() invokes ___ratelimit() which may invoke a normal
printk() (pr_warn() in this particular case) to warn about suppressed
output.  Given that printk_ratelimit() may be called from anywhere, that
pr_warn() is dangerous - it may end up deadlocking the system.  Fix
___ratelimit() by using deferred printk().

Sasha reported the following lockdep error:

 : Unregister pv shared memory for cpu 8
 : select_fallback_rq: 3 callbacks suppressed
 : process 8583 (trinity-c78) no longer affine to cpu8
 :
 : ======================================================
 : WARNING: possible circular locking dependency detected
 : 4.14.0-rc2-next-20170927+ torvalds#252 Not tainted
 : ------------------------------------------------------
 : migration/8/62 is trying to acquire lock:
 : (&port_lock_key){-.-.}, at: serial8250_console_write()
 :
 : but task is already holding lock:
 : (&rq->lock){-.-.}, at: sched_cpu_dying()
 :
 : which lock already depends on the new lock.
 :
 :
 : the existing dependency chain (in reverse order) is:
 :
 : -> l1k#3 (&rq->lock){-.-.}:
 : __lock_acquire()
 : lock_acquire()
 : _raw_spin_lock()
 : task_fork_fair()
 : sched_fork()
 : copy_process.part.31()
 : _do_fork()
 : kernel_thread()
 : rest_init()
 : start_kernel()
 : x86_64_start_reservations()
 : x86_64_start_kernel()
 : verify_cpu()
 :
 : -> l1k#2 (&p->pi_lock){-.-.}:
 : __lock_acquire()
 : lock_acquire()
 : _raw_spin_lock_irqsave()
 : try_to_wake_up()
 : default_wake_function()
 : woken_wake_function()
 : __wake_up_common()
 : __wake_up_common_lock()
 : __wake_up()
 : tty_wakeup()
 : tty_port_default_wakeup()
 : tty_port_tty_wakeup()
 : uart_write_wakeup()
 : serial8250_tx_chars()
 : serial8250_handle_irq.part.25()
 : serial8250_default_handle_irq()
 : serial8250_interrupt()
 : __handle_irq_event_percpu()
 : handle_irq_event_percpu()
 : handle_irq_event()
 : handle_level_irq()
 : handle_irq()
 : do_IRQ()
 : ret_from_intr()
 : native_safe_halt()
 : default_idle()
 : arch_cpu_idle()
 : default_idle_call()
 : do_idle()
 : cpu_startup_entry()
 : rest_init()
 : start_kernel()
 : x86_64_start_reservations()
 : x86_64_start_kernel()
 : verify_cpu()
 :
 : -> #1 (&tty->write_wait){-.-.}:
 : __lock_acquire()
 : lock_acquire()
 : _raw_spin_lock_irqsave()
 : __wake_up_common_lock()
 : __wake_up()
 : tty_wakeup()
 : tty_port_default_wakeup()
 : tty_port_tty_wakeup()
 : uart_write_wakeup()
 : serial8250_tx_chars()
 : serial8250_handle_irq.part.25()
 : serial8250_default_handle_irq()
 : serial8250_interrupt()
 : __handle_irq_event_percpu()
 : handle_irq_event_percpu()
 : handle_irq_event()
 : handle_level_irq()
 : handle_irq()
 : do_IRQ()
 : ret_from_intr()
 : native_safe_halt()
 : default_idle()
 : arch_cpu_idle()
 : default_idle_call()
 : do_idle()
 : cpu_startup_entry()
 : rest_init()
 : start_kernel()
 : x86_64_start_reservations()
 : x86_64_start_kernel()
 : verify_cpu()
 :
 : -> #0 (&port_lock_key){-.-.}:
 : check_prev_add()
 : __lock_acquire()
 : lock_acquire()
 : _raw_spin_lock_irqsave()
 : serial8250_console_write()
 : univ8250_console_write()
 : console_unlock()
 : vprintk_emit()
 : vprintk_default()
 : vprintk_func()
 : printk()
 : ___ratelimit()
 : __printk_ratelimit()
 : select_fallback_rq()
 : sched_cpu_dying()
 : cpuhp_invoke_callback()
 : take_cpu_down()
 : multi_cpu_stop()
 : cpu_stopper_thread()
 : smpboot_thread_fn()
 : kthread()
 : ret_from_fork()
 :
 : other info that might help us debug this:
 :
 : Chain exists of:
 :   &port_lock_key --> &p->pi_lock --> &rq->lock
 :
 :  Possible unsafe locking scenario:
 :
 :        CPU0                    CPU1
 :        ----                    ----
 :   lock(&rq->lock);
 :                                lock(&p->pi_lock);
 :                                lock(&rq->lock);
 :   lock(&port_lock_key);
 :
 :  *** DEADLOCK ***
 :
 : 4 locks held by migration/8/62:
 : #0: (&p->pi_lock){-.-.}, at: sched_cpu_dying()
 : #1: (&rq->lock){-.-.}, at: sched_cpu_dying()
 : l1k#2: (printk_ratelimit_state.lock){....}, at: ___ratelimit()
 : l1k#3: (console_lock){+.+.}, at: vprintk_emit()
 :
 : stack backtrace:
 : CPU: 8 PID: 62 Comm: migration/8 Not tainted 4.14.0-rc2-next-20170927+ torvalds#252
 : Call Trace:
 : dump_stack()
 : print_circular_bug()
 : check_prev_add()
 : ? add_lock_to_list.isra.26()
 : ? check_usage()
 : ? kvm_clock_read()
 : ? kvm_sched_clock_read()
 : ? sched_clock()
 : ? check_preemption_disabled()
 : __lock_acquire()
 : ? __lock_acquire()
 : ? add_lock_to_list.isra.26()
 : ? debug_check_no_locks_freed()
 : ? memcpy()
 : lock_acquire()
 : ? serial8250_console_write()
 : _raw_spin_lock_irqsave()
 : ? serial8250_console_write()
 : serial8250_console_write()
 : ? serial8250_start_tx()
 : ? lock_acquire()
 : ? memcpy()
 : univ8250_console_write()
 : console_unlock()
 : ? __down_trylock_console_sem()
 : vprintk_emit()
 : vprintk_default()
 : vprintk_func()
 : printk()
 : ? show_regs_print_info()
 : ? lock_acquire()
 : ___ratelimit()
 : __printk_ratelimit()
 : select_fallback_rq()
 : sched_cpu_dying()
 : ? sched_cpu_starting()
 : ? rcutree_dying_cpu()
 : ? sched_cpu_starting()
 : cpuhp_invoke_callback()
 : ? cpu_disable_common()
 : take_cpu_down()
 : ? trace_hardirqs_off_caller()
 : ? cpuhp_invoke_callback()
 : multi_cpu_stop()
 : ? __this_cpu_preempt_check()
 : ? cpu_stop_queue_work()
 : cpu_stopper_thread()
 : ? cpu_stop_create()
 : smpboot_thread_fn()
 : ? sort_range()
 : ? schedule()
 : ? __kthread_parkme()
 : kthread()
 : ? sort_range()
 : ? kthread_create_on_node()
 : ret_from_fork()
 : process 9121 (trinity-c78) no longer affine to cpu8
 : smpboot: CPU 8 is now offline

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 6b1d174 ("ratelimit: extend to print suppressed messages on release")
Signed-off-by: Sergey Senozhatsky <[email protected]>
Reported-by: Sasha Levin <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
roadrunner2 referenced this pull request in roadrunner2/linux Oct 12, 2017
flush_tlb_kernel_range() may call smp_call_function_many() which expects
interrupts to be enabled. This results in a traceback.

WARNING: CPU: 0 PID: 1 at kernel/smp.c:416 smp_call_function_many+0xcc/0x2fc
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.0-rc1-00009-g0666f56 #1
task: cf830000 task.stack: cf82e000
NIP:  c00a93c8 LR: c00a9634 CTR: 00000001
REGS: cf82fde0 TRAP: 0700   Not tainted  (4.14.0-rc1-00009-g0666f56)
MSR:  00021000 <CE,ME>  CR: 24000082  XER: 00000000

GPR00: c00a9634 cf82fe90 cf830000 c050ad3c c0015a54 00000000 00000001 00000001
GPR08: 00000001 00000000 00000000 cf82e000 24000084 00000000 c0003150 00000000
GPR16: 00000000 00000000 00000000 00000000 00000000 00000001 00000000 c051000
GPR24: 00000000 c0015a54 00000000 c050ad3c c051823c c050ad3c 00000025 00000000
NIP [c00a93c8] smp_call_function_many+0xcc/0x2fc
LR [c00a9634] smp_call_function+0x3c/0x50
Call Trace:
[cf82fe90] [00000010] 0x10 (unreliable)
[cf82fed0] [c00a9634] smp_call_function+0x3c/0x50
[cf82fee0] [c0015d2] flush_tlb_kernel_range+0x20/0x38
[cf82fef0] [c001524c] mark_initmem_nx+0x154/0x16c
[cf82ff20] [c001484c] free_initmem+0x20/0x4c
[cf82ff30] [c000316c] kernel_init+0x1c/0x108
[cf82ff40] [c000f3a8] ret_from_kernel_thread+0x5c/0x64
Instruction dump:
7c0803a6 7d808120 38210040 4e800020 3d20c052 812981a0 2f890000 40beffac
3d20c051 8929ac64 2f890000 40beff9c <0fe00000> 4bffff94 7fc3f378 7f64db78

Fixes: 3184cc4 ("powerpc/mm: Fix kernel RAM protection after freeing ...")
Fixes: e611939 ("powerpc/mm: Ensure change_page_attr() doesn't ...")
Cc: Christophe Leroy <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Reviewed-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
@roadrunner2
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It works! 🎉 Device got automatically attached. Great work!

FYI here is all related dmesg output:

[    3.194718] dw-apb-uart.1: ttyS4 at MMIO 0x8272a000 (irq = 21, base_baud = 115200) is a 16550A
[    3.195152] serial serial0: tty port ttyS4 registered
[    3.211904] dw-apb-uart.2: ttyS5 at MMIO 0x8272b000 (irq = 20, base_baud = 3000000) is a 16550A
[    3.212244] serial serial1: tty port ttyS5 registered
[    3.227479] dw-apb-uart.3: ttyS6 at MMIO 0x8272c000 (irq = 21, base_baud = 115200) is a 16550A
[    3.227751] serial serial2: tty port ttyS6 registered
[    9.123026] SELinux:  Class bluetooth_socket not defined in policy.
[   10.180684] synth uevent: /devices/pci0000:00/0000:00:19.0/dw-apb-uart.1/serial0: failed to send uevent
[   10.182831] synth uevent: /devices/pci0000:00/0000:00:1e.0/dw-apb-uart.2/serial1: failed to send uevent
[   10.183808] synth uevent: /devices/pci0000:00/0000:00:1e.1/dw-apb-uart.3/serial2: failed to send uevent
[   10.404890] Bluetooth: Core ver 2.22
[   10.404993] Bluetooth: HCI device and connection manager initialized
[   10.405122] Bluetooth: HCI socket layer initialized
[   10.405132] Bluetooth: L2CAP socket layer initialized
[   10.405236] Bluetooth: SCO socket layer initialized
[   10.435054] Bluetooth: HCI UART driver ver 2.3
[   10.435061] Bluetooth: HCI UART protocol H4 registered
[   10.435066] Bluetooth: HCI UART protocol BCSP registered
[   10.435196] Bluetooth: HCI UART protocol LL registered
[   10.435200] Bluetooth: HCI UART protocol ATH3K registered
[   10.435203] Bluetooth: HCI UART protocol Three-wire (H5) registered
[   10.441639] Bluetooth: HCI UART protocol Intel registered
[   10.441848] Bluetooth: HCI UART protocol Broadcom registered
[   10.441853] Bluetooth: HCI UART protocol QCA registered
[   10.441857] Bluetooth: HCI UART protocol AG6XX registered
[   10.441862] Bluetooth: HCI UART protocol Marvell registered
[   10.442029] hci_uart_bcm serial1-0: BCM irq: -22
[   10.455816] dw-apb-uart dw-apb-uart.2: Looking for DMA channel "rx" at index 1...
[   10.455926] ttyS5 - failed to request DMA
[   10.715458] Bluetooth: hci0: BCM: failed to write update baudrate (-16)
[   10.715471] Bluetooth: hci0: failed to set baudrate
[   10.827304] Bluetooth: hci0: BCM: chip id 126
[   10.828714] Bluetooth: hci0: BCM: features 0x2f
[   10.837984] Bluetooth: hci0: BCM20703A2 Generic UART UHE Apple 40MHz wlcsp_x100
[   10.837990] Bluetooth: hci0: BCM (001.002.048) build 0131
[   10.838214] bluetooth hci0: Direct firmware load for brcm/BCM.hcd failed with error -2
[   10.838235] Bluetooth: hci0: BCM: Patch brcm/BCM.hcd not found
[   13.743577] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[   13.743581] Bluetooth: BNEP filters: protocol multicast
[   13.743587] Bluetooth: BNEP socket layer initialized
[   24.114250] Bluetooth: RFCOMM TTY layer initialized
[   24.114263] Bluetooth: RFCOMM socket layer initialized
[   24.114315] Bluetooth: RFCOMM ver 1.11

@peterychuang
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I can confirm the patches work on the latest linux-next tree. Thanks for your work!

PS @l1k if you don't mind, could you change my cc email in the commit to peteryuchuang at gmail dot com? Thanks.

@l1k
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l1k commented Oct 13, 2017

Thanks a lot for testing! I'll have to do a bit more code reading and analysis of @roadrunner2's dmesg output to finalize the patch. The issue that a timeout occurs, does this still exist? With serdev, you can no longer stop and restart hciattach to work around it...

@roadrunner2: About the proto-locks patch: I've realized only now that hci_ldisc.c is apparently no longer used in favor of hci_serdev.c. Since the patch changes the former, it seems it's not really necessary. The legacy code which uses a line discipline to signify that a Bluetooth device is attached currently coexists with the newer serdev code, it's quite a mess and I'm having trouble wrapping my head around it myself. The good news is that hci_bcm seems to be the first driver converted to the new infrastructure and we can piggyback on this effort and avoid trouble with a later conversion to serdev.

I can't really connect the proto-locks patch with the stacktraces you've posted above: They refer to a struct mutex, which is indeed a sleeping lock that can't be used in atomic/interrupt context, but the patch changes an rwlock_t, so a different locking primitive.

So, looking at the second stacktrace, we can see that mutex_lock() was called from bcm_recv(). There is some stuff about hci_recv_frame() and h4_recv_buf() above that but it looks bogus. Sometimes stacktraces contain garbage like that, the new ORC unwinder is said to be more reliable. But anyway, if I look at bcm_recv(), there's indeed a call to mutex_lock() there which is invoked if h4_recv_buf() returned NULL. So the question is, why did it return NULL? Was that correct in the given situation? And the BUG occurred because in_atomic() was true at that point. Hmmm, no idea if there's an actual bug here or if this was an issue with the rc kernel that I had based the hci_bcm branch on, or something else entirely...

@peterychuang: Sure, I've updated your e-mail address and pushed the branch, again rebased on current bluetooth-next.

@roadrunner2
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@l1k Regarding the locking: the mutex is in hci_bcm, so lower down in call chain; the rwlock (which doesn't allow sleeping) is acquired in hci_ldisc, which is higher up in the call chain. More specifically: hci_uart_tty_receive and hci_uart_write_work both acquire the rwlock - those entries in the stack trace are real ones (well, hci_uart_write_lock inlines hci_uart_dequeue which is the one actually taking the lock and calling down to proto->dequeue). With the rwlock held, both of these then call down to the respective proto callbacks, which in this case are bcm_recv and bcm_dequeue. And those two directly acquire the mutex.

Regarding h4_recv_buf returning null, that appears to signal a complete frame - see comment near the bottom of that function. In any case, even if that would be bug (though since bcm_recv explicitly tests for this case, I think it's very much intentional), the write (dequeue) path has the same locking issue.

Now, AFAICT we can't replace the mutex in hci_bcm with something non-sleeping, so we have to change the rwlock instead to something that allows sleeping - that is a more general fix anyway (i.e. allows any proto implementation to use any lock it wants).

I looked at hci_serdev and that doesn't have this issue because it doesn't do any locking itself.

So for bluetooth-next it appears the lock patch isn't strictly necessary, but for 4.14?

Lastly, regarding the timeout, no, haven't seen it yet, but haven't done much testing - will bang at it some more and let you know.

l1k pushed a commit that referenced this pull request Oct 4, 2025
There is a potential deadlock that can happen in
try_release_subpage_extent_buffer() because the irq-safe xarray spin
lock fs_info->buffer_tree is being acquired before the irq-unsafe
eb->refs_lock.

This leads to the potential race:
// T1 (random eb->refs user)                  // T2 (release folio)

spin_lock(&eb->refs_lock);
// interrupt
end_bbio_meta_write()
  btrfs_meta_folio_clear_writeback()
                                              btree_release_folio()
                                                folio_test_writeback() //false
                                                try_release_extent_buffer()
                                                  try_release_subpage_extent_buffer()
                                                    xa_lock_irq(&fs_info->buffer_tree)
                                                    spin_lock(&eb->refs_lock); // blocked; held by T1
  buffer_tree_clear_mark()
    xas_lock_irqsave() // blocked; held by T2

I believe that the spin lock can safely be replaced by an rcu_read_lock.
The xa_for_each loop does not need the spin lock as it's already
internally protected by the rcu_read_lock. The extent buffer is also
protected by the rcu_read_lock so it won't be freed before we take the
eb->refs_lock and check the ref count.

The rcu_read_lock is taken and released every iteration, just like the
spin lock, which means we're not protected against concurrent
insertions into the xarray. This is fine because we rely on
folio->private to detect if there are any ebs remaining in the folio.

There is already some precedent for this with find_extent_buffer_nolock,
which loads an extent buffer from the xarray with only rcu_read_lock.

lockdep warning:

            =====================================================
            WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
            6.16.0-0_fbk701_debug_rc0_123_g4c06e63b9203 #1 Tainted: G E    N
            -----------------------------------------------------
            kswapd0/66 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
            ffff000011ffd600 (&eb->refs_lock){+.+.}-{3:3}, at: try_release_extent_buffer+0x18c/0x560

and this task is already holding:
            ffff0000c1d91b88 (&buffer_xa_class){-.-.}-{3:3}, at: try_release_extent_buffer+0x13c/0x560
            which would create a new lock dependency:
             (&buffer_xa_class){-.-.}-{3:3} -> (&eb->refs_lock){+.+.}-{3:3}

but this new dependency connects a HARDIRQ-irq-safe lock:
             (&buffer_xa_class){-.-.}-{3:3}

... which became HARDIRQ-irq-safe at:
              lock_acquire+0x178/0x358
              _raw_spin_lock_irqsave+0x60/0x88
              buffer_tree_clear_mark+0xc4/0x160
              end_bbio_meta_write+0x238/0x398
              btrfs_bio_end_io+0x1f8/0x330
              btrfs_orig_write_end_io+0x1c4/0x2c0
              bio_endio+0x63c/0x678
              blk_update_request+0x1c4/0xa00
              blk_mq_end_request+0x54/0x88
              virtblk_request_done+0x124/0x1d0
              blk_mq_complete_request+0x84/0xa0
              virtblk_done+0x130/0x238
              vring_interrupt+0x130/0x288
              __handle_irq_event_percpu+0x1e8/0x708
              handle_irq_event+0x98/0x1b0
              handle_fasteoi_irq+0x264/0x7c0
              generic_handle_domain_irq+0xa4/0x108
              gic_handle_irq+0x7c/0x1a0
              do_interrupt_handler+0xe4/0x148
              el1_interrupt+0x30/0x50
              el1h_64_irq_handler+0x14/0x20
              el1h_64_irq+0x6c/0x70
              _raw_spin_unlock_irq+0x38/0x70
              __run_timer_base+0xdc/0x5e0
              run_timer_softirq+0xa0/0x138
              handle_softirqs.llvm.13542289750107964195+0x32c/0xbd0
              ____do_softirq.llvm.17674514681856217165+0x18/0x28
              call_on_irq_stack+0x24/0x30
              __irq_exit_rcu+0x164/0x430
              irq_exit_rcu+0x18/0x88
              el1_interrupt+0x34/0x50
              el1h_64_irq_handler+0x14/0x20
              el1h_64_irq+0x6c/0x70
              arch_local_irq_enable+0x4/0x8
              do_idle+0x1a0/0x3b8
              cpu_startup_entry+0x60/0x80
              rest_init+0x204/0x228
              start_kernel+0x394/0x3f0
              __primary_switched+0x8c/0x8958

to a HARDIRQ-irq-unsafe lock:
             (&eb->refs_lock){+.+.}-{3:3}

... which became HARDIRQ-irq-unsafe at:
            ...
              lock_acquire+0x178/0x358
              _raw_spin_lock+0x4c/0x68
              free_extent_buffer_stale+0x2c/0x170
              btrfs_read_sys_array+0x1b0/0x338
              open_ctree+0xeb0/0x1df8
              btrfs_get_tree+0xb60/0x1110
              vfs_get_tree+0x8c/0x250
              fc_mount+0x20/0x98
              btrfs_get_tree+0x4a4/0x1110
              vfs_get_tree+0x8c/0x250
              do_new_mount+0x1e0/0x6c0
              path_mount+0x4ec/0xa58
              __arm64_sys_mount+0x370/0x490
              invoke_syscall+0x6c/0x208
              el0_svc_common+0x14c/0x1b8
              do_el0_svc+0x4c/0x60
              el0_svc+0x4c/0x160
              el0t_64_sync_handler+0x70/0x100
              el0t_64_sync+0x168/0x170

other info that might help us debug this:
             Possible interrupt unsafe locking scenario:
                   CPU0                    CPU1
                   ----                    ----
              lock(&eb->refs_lock);
                                           local_irq_disable();
                                           lock(&buffer_xa_class);
                                           lock(&eb->refs_lock);
              <Interrupt>
                lock(&buffer_xa_class);

  *** DEADLOCK ***
            2 locks held by kswapd0/66:
             #0: ffff800085506e40 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0xe8/0xe50
             #1: ffff0000c1d91b88 (&buffer_xa_class){-.-.}-{3:3}, at: try_release_extent_buffer+0x13c/0x560

Link: https://www.kernel.org/doc/Documentation/locking/lockdep-design.rst#:~:text=Multi%2Dlock%20dependency%20rules%3A
Fixes: 19d7f65 ("btrfs: convert the buffer_radix to an xarray")
CC: [email protected] # 6.16+
Reviewed-by: Boris Burkov <[email protected]>
Reviewed-by: Qu Wenruo <[email protected]>
Signed-off-by: Leo Martins <[email protected]>
Signed-off-by: David Sterba <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
The check_pmd_still_valid() call during collapse is currently only
protected by the mmap_lock in write mode, which was sufficient when
pt_reclaim always ran under mmap_lock in read mode.  However, since
madvise_dontneed can now execute under a per-VMA lock, this assumption is
no longer valid.  As a result, a race condition can occur between collapse
and PT_RECLAIM, potentially leading to a kernel panic.

 [   38.151897] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] SMP KASI
 [   38.153519] KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
 [   38.154605] CPU: 0 UID: 0 PID: 721 Comm: repro Not tainted 6.16.0-next-20250801-next-2025080 #1 PREEMPT(voluntary)
 [   38.155929] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org4
 [   38.157418] RIP: 0010:kasan_byte_accessible+0x15/0x30
 [   38.158125] Code: 03 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 66 0f 1f 00 48 b8 00 00 00 00 00 fc0
 [   38.160461] RSP: 0018:ffff88800feef678 EFLAGS: 00010286
 [   38.161220] RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 1ffffffff0dde60c
 [   38.162232] RDX: 0000000000000000 RSI: ffffffff85da1e18 RDI: dffffc0000000003
 [   38.163176] RBP: ffff88800feef698 R08: 0000000000000001 R09: 0000000000000000
 [   38.164195] R10: 0000000000000000 R11: ffff888016a8ba58 R12: 0000000000000018
 [   38.165189] R13: 0000000000000018 R14: ffffffff85da1e18 R15: 0000000000000000
 [   38.166100] FS:  0000000000000000(0000) GS:ffff8880e3b40000(0000) knlGS:0000000000000000
 [   38.167137] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 [   38.167891] CR2: 00007f97fadfe504 CR3: 0000000007088005 CR4: 0000000000770ef0
 [   38.168812] PKRU: 55555554
 [   38.169275] Call Trace:
 [   38.169647]  <TASK>
 [   38.169975]  ? __kasan_check_byte+0x19/0x50
 [   38.170581]  lock_acquire+0xea/0x310
 [   38.171083]  ? rcu_is_watching+0x19/0xc0
 [   38.171615]  ? __sanitizer_cov_trace_const_cmp4+0x1a/0x20
 [   38.172343]  ? __sanitizer_cov_trace_const_cmp8+0x1c/0x30
 [   38.173130]  _raw_spin_lock+0x38/0x50
 [   38.173707]  ? __pte_offset_map_lock+0x1a2/0x3c0
 [   38.174390]  __pte_offset_map_lock+0x1a2/0x3c0
 [   38.174987]  ? __pfx___pte_offset_map_lock+0x10/0x10
 [   38.175724]  ? __pfx_pud_val+0x10/0x10
 [   38.176308]  ? __sanitizer_cov_trace_const_cmp1+0x1e/0x30
 [   38.177183]  unmap_page_range+0xb60/0x43e0
 [   38.177824]  ? __pfx_unmap_page_range+0x10/0x10
 [   38.178485]  ? mas_next_slot+0x133a/0x1a50
 [   38.179079]  unmap_single_vma.constprop.0+0x15b/0x250
 [   38.179830]  unmap_vmas+0x1fa/0x460
 [   38.180373]  ? __pfx_unmap_vmas+0x10/0x10
 [   38.180994]  ? __sanitizer_cov_trace_const_cmp4+0x1a/0x20
 [   38.181877]  exit_mmap+0x1a2/0xb40
 [   38.182396]  ? lock_release+0x14f/0x2c0
 [   38.182929]  ? __pfx_exit_mmap+0x10/0x10
 [   38.183474]  ? __pfx___mutex_unlock_slowpath+0x10/0x10
 [   38.184188]  ? mutex_unlock+0x16/0x20
 [   38.184704]  mmput+0x132/0x370
 [   38.185208]  do_exit+0x7e7/0x28c0
 [   38.185682]  ? __this_cpu_preempt_check+0x21/0x30
 [   38.186328]  ? do_group_exit+0x1d8/0x2c0
 [   38.186873]  ? __pfx_do_exit+0x10/0x10
 [   38.187401]  ? __this_cpu_preempt_check+0x21/0x30
 [   38.188036]  ? _raw_spin_unlock_irq+0x2c/0x60
 [   38.188634]  ? lockdep_hardirqs_on+0x89/0x110
 [   38.189313]  do_group_exit+0xe4/0x2c0
 [   38.189831]  __x64_sys_exit_group+0x4d/0x60
 [   38.190413]  x64_sys_call+0x2174/0x2180
 [   38.190935]  do_syscall_64+0x6d/0x2e0
 [   38.191449]  entry_SYSCALL_64_after_hwframe+0x76/0x7e

This patch moves the vma_start_write() call to precede
check_pmd_still_valid(), ensuring that the check is also properly
protected by the per-VMA lock.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: a6fde7a ("mm: use per_vma lock for MADV_DONTNEED")
Signed-off-by: Barry Song <[email protected]>
Tested-by: "Lai, Yi" <[email protected]>
Reported-by: "Lai, Yi" <[email protected]>
Closes: https://lore.kernel.org/all/aJAFrYfyzGpbm+0m@ly-workstation/
Reviewed-by: Lorenzo Stoakes <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Qi Zheng <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Lokesh Gidra <[email protected]>
Cc: Tangquan Zheng <[email protected]>
Cc: Lance Yang <[email protected]>
Cc: Zi Yan <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Nico Pache <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Dev Jain <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
Since EROFS handles decompression in non-atomic contexts due to
uncontrollable decompression latencies and vmap() usage, it tries
to detect atomic contexts and only kicks off a kworker on demand
in order to reduce unnecessary scheduling overhead.

However, the current approach is insufficient and can lead to
sleeping function calls in invalid contexts, causing kernel
warnings and potential system instability. See the stacktrace [1]
and previous discussion [2].

The current implementation only checks rcu_read_lock_any_held(),
which behaves inconsistently across different kernel configurations:

- When CONFIG_DEBUG_LOCK_ALLOC is enabled: correctly detects
  RCU critical sections by checking rcu_lock_map
- When CONFIG_DEBUG_LOCK_ALLOC is disabled: compiles to
  "!preemptible()", which only checks preempt_count and misses
  RCU critical sections

This patch introduces z_erofs_in_atomic() to provide comprehensive
atomic context detection:

1. Check RCU preemption depth when CONFIG_PREEMPTION is enabled,
   as RCU critical sections may not affect preempt_count but still
   require atomic handling

2. Always use async processing when CONFIG_PREEMPT_COUNT is disabled,
   as preemption state cannot be reliably determined

3. Fall back to standard preemptible() check for remaining cases

The function replaces the previous complex condition check and ensures
that z_erofs always uses (kthread_)work in atomic contexts to minimize
scheduling overhead and prevent sleeping in invalid contexts.

[1] Problem stacktrace
[ 61.266692] BUG: sleeping function called from invalid context at kernel/locking/rtmutex_api.c:510
[ 61.266702] in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 107, name: irq/54-ufshcd
[ 61.266704] preempt_count: 0, expected: 0
[ 61.266705] RCU nest depth: 2, expected: 0
[ 61.266710] CPU: 0 UID: 0 PID: 107 Comm: irq/54-ufshcd Tainted: G W O 6.12.17 #1
[ 61.266714] Tainted: [W]=WARN, [O]=OOT_MODULE
[ 61.266715] Hardware name: schumacher (DT)
[ 61.266717] Call trace:
[ 61.266718] dump_backtrace+0x9c/0x100
[ 61.266727] show_stack+0x20/0x38
[ 61.266728] dump_stack_lvl+0x78/0x90
[ 61.266734] dump_stack+0x18/0x28
[ 61.266736] __might_resched+0x11c/0x180
[ 61.266743] __might_sleep+0x64/0xc8
[ 61.266745] mutex_lock+0x2c/0xc0
[ 61.266748] z_erofs_decompress_queue+0xe8/0x978
[ 61.266753] z_erofs_decompress_kickoff+0xa8/0x190
[ 61.266756] z_erofs_endio+0x168/0x288
[ 61.266758] bio_endio+0x160/0x218
[ 61.266762] blk_update_request+0x244/0x458
[ 61.266766] scsi_end_request+0x38/0x278
[ 61.266770] scsi_io_completion+0x4c/0x600
[ 61.266772] scsi_finish_command+0xc8/0xe8
[ 61.266775] scsi_complete+0x88/0x148
[ 61.266777] blk_mq_complete_request+0x3c/0x58
[ 61.266780] scsi_done_internal+0xcc/0x158
[ 61.266782] scsi_done+0x1c/0x30
[ 61.266783] ufshcd_compl_one_cqe+0x12c/0x438
[ 61.266786] __ufshcd_transfer_req_compl+0x2c/0x78
[ 61.266788] ufshcd_poll+0xf4/0x210
[ 61.266789] ufshcd_transfer_req_compl+0x50/0x88
[ 61.266791] ufshcd_intr+0x21c/0x7c8
[ 61.266792] irq_forced_thread_fn+0x44/0xd8
[ 61.266796] irq_thread+0x1a4/0x358
[ 61.266799] kthread+0x12c/0x138
[ 61.266802] ret_from_fork+0x10/0x20

[2] https://lore.kernel.org/r/58b661d0-0ebb-4b45-a10d-c5927fb791cd@paulmck-laptop

Signed-off-by: Junli Liu <[email protected]>
Reviewed-by: Gao Xiang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
[ Gao Xiang: Use the original trace in v1. ]
Signed-off-by: Gao Xiang <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
The existing code move the VF NIC to new namespace when NETDEV_REGISTER is
received on netvsc NIC. During deletion of the namespace,
default_device_exit_batch() >> default_device_exit_net() is called. When
netvsc NIC is moved back and registered to the default namespace, it
automatically brings VF NIC back to the default namespace. This will cause
the default_device_exit_net() >> for_each_netdev_safe loop unable to detect
the list end, and hit NULL ptr:

[  231.449420] mana 7870:00:00.0 enP30832s1: Moved VF to namespace with: eth0
[  231.449656] BUG: kernel NULL pointer dereference, address: 0000000000000010
[  231.450246] #PF: supervisor read access in kernel mode
[  231.450579] #PF: error_code(0x0000) - not-present page
[  231.450916] PGD 17b8a8067 P4D 0
[  231.451163] Oops: Oops: 0000 [#1] SMP NOPTI
[  231.451450] CPU: 82 UID: 0 PID: 1394 Comm: kworker/u768:1 Not tainted 6.16.0-rc4+ #3 VOLUNTARY
[  231.452042] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 11/21/2024
[  231.452692] Workqueue: netns cleanup_net
[  231.452947] RIP: 0010:default_device_exit_batch+0x16c/0x3f0
[  231.453326] Code: c0 0c f5 b3 e8 d5 db fe ff 48 85 c0 74 15 48 c7 c2 f8 fd ca b2 be 10 00 00 00 48 8d 7d c0 e8 7b 77 25 00 49 8b 86 28 01 00 00 <48> 8b 50 10 4c 8b 2a 4c 8d 62 f0 49 83 ed 10 4c 39 e0 0f 84 d6 00
[  231.454294] RSP: 0018:ff75fc7c9bf9fd00 EFLAGS: 00010246
[  231.454610] RAX: 0000000000000000 RBX: 0000000000000002 RCX: 61c8864680b583eb
[  231.455094] RDX: ff1fa9f71462d800 RSI: ff75fc7c9bf9fd38 RDI: 0000000030766564
[  231.455686] RBP: ff75fc7c9bf9fd78 R08: 0000000000000000 R09: 0000000000000000
[  231.456126] R10: 0000000000000001 R11: 0000000000000004 R12: ff1fa9f70088e340
[  231.456621] R13: ff1fa9f70088e340 R14: ffffffffb3f50c20 R15: ff1fa9f7103e6340
[  231.457161] FS:  0000000000000000(0000) GS:ff1faa6783a08000(0000) knlGS:0000000000000000
[  231.457707] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  231.458031] CR2: 0000000000000010 CR3: 0000000179ab2006 CR4: 0000000000b73ef0
[  231.458434] Call Trace:
[  231.458600]  <TASK>
[  231.458777]  ops_undo_list+0x100/0x220
[  231.459015]  cleanup_net+0x1b8/0x300
[  231.459285]  process_one_work+0x184/0x340

To fix it, move the ns change to a workqueue, and take rtnl_lock to avoid
changing the netdev list when default_device_exit_net() is using it.

Cc: [email protected]
Fixes: 4c26280 ("hv_netvsc: Fix VF namespace also in synthetic NIC NETDEV_REGISTER event")
Signed-off-by: Haiyang Zhang <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
syzbot reported the splat below. [0]

When nsim_queue_uninit() is called from nsim_init_netdevsim(),
register_netdevice() has not been called, thus dev->dstats has
not been allocated.

Let's not call dev_dstats_rx_dropped_add() in such a case.

[0]
BUG: unable to handle page fault for address: ffff88809782c020
 PF: supervisor write access in kernel mode
 PF: error_code(0x0002) - not-present page
PGD 1b401067 P4D 1b401067 PUD 0
Oops: Oops: 0002 [#1] SMP KASAN NOPTI
CPU: 3 UID: 0 PID: 8476 Comm: syz.1.251 Not tainted 6.16.0-syzkaller-06699-ge8d780dcd957 #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:local_add arch/x86/include/asm/local.h:33 [inline]
RIP: 0010:u64_stats_add include/linux/u64_stats_sync.h:89 [inline]
RIP: 0010:dev_dstats_rx_dropped_add include/linux/netdevice.h:3027 [inline]
RIP: 0010:nsim_queue_free+0xba/0x120 drivers/net/netdevsim/netdev.c:714
Code: 07 77 6c 4a 8d 3c ed 20 7e f1 8d 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 46 4a 03 1c ed 20 7e f1 8d <4c> 01 63 20 be 00 02 00 00 48 8d 3d 00 00 00 00 e8 61 2f 58 fa 48
RSP: 0018:ffffc900044af150 EFLAGS: 00010286
RAX: dffffc0000000000 RBX: ffff88809782c000 RCX: 00000000000079c3
RDX: 1ffffffff1be2fc7 RSI: ffffffff8c15f380 RDI: ffffffff8df17e38
RBP: ffff88805f59d000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000003 R14: ffff88806ceb3d00 R15: ffffed100dfd308e
FS:  0000000000000000(0000) GS:ffff88809782c000(0063) knlGS:00000000f505db40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffff88809782c020 CR3: 000000006fc6a000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 nsim_queue_uninit drivers/net/netdevsim/netdev.c:993 [inline]
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1049 [inline]
 nsim_create+0xd0a/0x1260 drivers/net/netdevsim/netdev.c:1101
 __nsim_dev_port_add+0x435/0x7d0 drivers/net/netdevsim/dev.c:1438
 nsim_dev_port_add_all drivers/net/netdevsim/dev.c:1494 [inline]
 nsim_dev_reload_create drivers/net/netdevsim/dev.c:1546 [inline]
 nsim_dev_reload_up+0x5b8/0x860 drivers/net/netdevsim/dev.c:1003
 devlink_reload+0x322/0x7c0 net/devlink/dev.c:474
 devlink_nl_reload_doit+0xe31/0x1410 net/devlink/dev.c:584
 genl_family_rcv_msg_doit+0x206/0x2f0 net/netlink/genetlink.c:1115
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2552
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg net/socket.c:729 [inline]
 ____sys_sendmsg+0xa95/0xc70 net/socket.c:2614
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2668
 __sys_sendmsg+0x16d/0x220 net/socket.c:2700
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf708e579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f505d55c EFLAGS: 00000296 ORIG_RAX: 0000000000000172
RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 0000000080000080
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
CR2: ffff88809782c020

Fixes: 2a68a22 ("netdevsim: account dropped packet length in stats on queue free")
Reported-by: [email protected]
Closes: https://lore.kernel.org/netdev/[email protected]/
Suggested-by: Jakub Kicinski <[email protected]>
Signed-off-by: Kuniyuki Iwashima <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
Shuang reported sch_ets test-case [1] crashing in ets_class_qlen_notify()
after recent changes from Lion [2]. The problem is: in ets_qdisc_change()
we purge unused DWRR queues; the value of 'q->nbands' is the new one, and
the cleanup should be done with the old one. The problem is here since my
first attempts to fix ets_qdisc_change(), but it surfaced again after the
recent qdisc len accounting fixes. Fix it purging idle DWRR queues before
assigning a new value of 'q->nbands', so that all purge operations find a
consistent configuration:

 - old 'q->nbands' because it's needed by ets_class_find()
 - old 'q->nstrict' because it's needed by ets_class_is_strict()

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: Oops: 0000 [#1] SMP NOPTI
 CPU: 62 UID: 0 PID: 39457 Comm: tc Kdump: loaded Not tainted 6.12.0-116.el10.x86_64 #1 PREEMPT(voluntary)
 Hardware name: Dell Inc. PowerEdge R640/06DKY5, BIOS 2.12.2 07/09/2021
 RIP: 0010:__list_del_entry_valid_or_report+0x4/0x80
 Code: ff 4c 39 c7 0f 84 39 19 8e ff b8 01 00 00 00 c3 cc cc cc cc 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa <48> 8b 17 48 8b 4f 08 48 85 d2 0f 84 56 19 8e ff 48 85 c9 0f 84 ab
 RSP: 0018:ffffba186009f400 EFLAGS: 00010202
 RAX: 00000000000000d6 RBX: 0000000000000000 RCX: 0000000000000004
 RDX: ffff9f0fa29b69c0 RSI: 0000000000000000 RDI: 0000000000000000
 RBP: ffffffffc12c2400 R08: 0000000000000008 R09: 0000000000000004
 R10: ffffffffffffffff R11: 0000000000000004 R12: 0000000000000000
 R13: ffff9f0f8cfe0000 R14: 0000000000100005 R15: 0000000000000000
 FS:  00007f2154f37480(0000) GS:ffff9f269c1c0000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000000 CR3: 00000001530be001 CR4: 00000000007726f0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 PKRU: 55555554
 Call Trace:
  <TASK>
  ets_class_qlen_notify+0x65/0x90 [sch_ets]
  qdisc_tree_reduce_backlog+0x74/0x110
  ets_qdisc_change+0x630/0xa40 [sch_ets]
  __tc_modify_qdisc.constprop.0+0x216/0x7f0
  tc_modify_qdisc+0x7c/0x120
  rtnetlink_rcv_msg+0x145/0x3f0
  netlink_rcv_skb+0x53/0x100
  netlink_unicast+0x245/0x390
  netlink_sendmsg+0x21b/0x470
  ____sys_sendmsg+0x39d/0x3d0
  ___sys_sendmsg+0x9a/0xe0
  __sys_sendmsg+0x7a/0xd0
  do_syscall_64+0x7d/0x160
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7f2155114084
 Code: 89 02 b8 ff ff ff ff eb bb 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 80 3d 25 f0 0c 00 00 74 13 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 89 54 24 1c 48 89
 RSP: 002b:00007fff1fd7a988 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
 RAX: ffffffffffffffda RBX: 0000560ec063e5e0 RCX: 00007f2155114084
 RDX: 0000000000000000 RSI: 00007fff1fd7a9f0 RDI: 0000000000000003
 RBP: 00007fff1fd7aa60 R08: 0000000000000010 R09: 000000000000003f
 R10: 0000560ee9b3a010 R11: 0000000000000202 R12: 00007fff1fd7aae0
 R13: 000000006891ccde R14: 0000560ec063e5e0 R15: 00007fff1fd7aad0
  </TASK>

 [1] https://lore.kernel.org/netdev/e08c7f4a6882f260011909a868311c6e9b54f3e4.1639153474.git.dcaratti@redhat.com/
 [2] https://lore.kernel.org/netdev/[email protected]/

Cc: [email protected]
Fixes: 103406b ("net/sched: Always pass notifications when child class becomes empty")
Fixes: c062f2a ("net/sched: sch_ets: don't remove idle classes from the round-robin list")
Fixes: dcc68b4 ("net: sch_ets: Add a new Qdisc")
Reported-by: Li Shuang <[email protected]>
Closes: https://issues.redhat.com/browse/RHEL-108026
Reviewed-by: Petr Machata <[email protected]>
Co-developed-by: Ivan Vecera <[email protected]>
Signed-off-by: Ivan Vecera <[email protected]>
Signed-off-by: Davide Caratti <[email protected]>
Link: https://patch.msgid.link/7928ff6d17db47a2ae7cc205c44777b1f1950545.1755016081.git.dcaratti@redhat.com
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
btrfs_subpage_set_writeback() calls folio_start_writeback() the first time
a folio is written back, and it also clears the PAGECACHE_TAG_TOWRITE tag
even if there are still dirty blocks in the folio. This can break ordering
guarantees, such as those required by btrfs_wait_ordered_extents().

That ordering breakage leads to a real failure. For example, running
generic/464 on a zoned setup will hit the following ASSERT. This happens
because the broken ordering fails to flush existing dirty pages before the
file size is truncated.

  assertion failed: !list_empty(&ordered->list) :: 0, in fs/btrfs/zoned.c:1899
  ------------[ cut here ]------------
  kernel BUG at fs/btrfs/zoned.c:1899!
  Oops: invalid opcode: 0000 [#1] SMP NOPTI
  CPU: 2 UID: 0 PID: 1906169 Comm: kworker/u130:2 Kdump: loaded Not tainted 6.16.0-rc6-BTRFS-ZNS+ torvalds#554 PREEMPT(voluntary)
  Hardware name: Supermicro Super Server/H12SSL-NT, BIOS 2.0 02/22/2021
  Workqueue: btrfs-endio-write btrfs_work_helper [btrfs]
  RIP: 0010:btrfs_finish_ordered_zoned.cold+0x50/0x52 [btrfs]
  RSP: 0018:ffffc9002efdbd60 EFLAGS: 00010246
  RAX: 000000000000004c RBX: ffff88811923c4e0 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: ffffffff827e38b1 RDI: 00000000ffffffff
  RBP: ffff88810005d000 R08: 00000000ffffdfff R09: ffffffff831051c8
  R10: ffffffff83055220 R11: 0000000000000000 R12: ffff8881c2458c00
  R13: ffff88811923c540 R14: ffff88811923c5e8 R15: ffff8881c1bd9680
  FS:  0000000000000000(0000) GS:ffff88a04acd0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f907c7a918c CR3: 0000000004024000 CR4: 0000000000350ef0
  Call Trace:
   <TASK>
   ? srso_return_thunk+0x5/0x5f
   btrfs_finish_ordered_io+0x4a/0x60 [btrfs]
   btrfs_work_helper+0xf9/0x490 [btrfs]
   process_one_work+0x204/0x590
   ? srso_return_thunk+0x5/0x5f
   worker_thread+0x1d6/0x3d0
   ? __pfx_worker_thread+0x10/0x10
   kthread+0x118/0x230
   ? __pfx_kthread+0x10/0x10
   ret_from_fork+0x205/0x260
   ? __pfx_kthread+0x10/0x10
   ret_from_fork_asm+0x1a/0x30
   </TASK>

Consider process A calling writepages() with WB_SYNC_NONE. In zoned mode or
for compressed writes, it locks several folios for delalloc and starts
writing them out. Let's call the last locked folio folio X. Suppose the
write range only partially covers folio X, leaving some pages dirty.
Process A calls btrfs_subpage_set_writeback() when building a bio. This
function call clears the TOWRITE tag of folio X, whose size = 8K and
the block size = 4K. It is following state.

   0     4K    8K
   |/////|/////|  (flag: DIRTY, tag: DIRTY)
   <-----> Process A will write this range.

Now suppose process B concurrently calls writepages() with WB_SYNC_ALL. It
calls tag_pages_for_writeback() to tag dirty folios with
PAGECACHE_TAG_TOWRITE. Since folio X is still dirty, it gets tagged. Then,
B collects tagged folios using filemap_get_folios_tag() and must wait for
folio X to be written before returning from writepages().

   0     4K    8K
   |/////|/////|  (flag: DIRTY, tag: DIRTY|TOWRITE)

However, between tagging and collecting, process A may call
btrfs_subpage_set_writeback() and clear folio X's TOWRITE tag.
   0     4K    8K
   |     |/////|  (flag: DIRTY|WRITEBACK, tag: DIRTY)

As a result, process B won't see folio X in its batch, and returns without
waiting for it. This breaks the WB_SYNC_ALL ordering requirement.

Fix this by using btrfs_subpage_set_writeback_keepwrite(), which retains
the TOWRITE tag. We now manually clear the tag only after the folio becomes
clean, via the xas operation.

Fixes: 3470da3 ("btrfs: subpage: introduce helpers for writeback status")
CC: [email protected] # 6.12+
Reviewed-by: Qu Wenruo <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Naohiro Aota <[email protected]>
Signed-off-by: David Sterba <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
An use-after-free issue occurred when __mark_inode_dirty() get the
bdi_writeback that was in the progress of switching.

CPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1
......
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __mark_inode_dirty+0x124/0x418
lr : __mark_inode_dirty+0x118/0x418
sp : ffffffc08c9dbbc0
........
Call trace:
 __mark_inode_dirty+0x124/0x418
 generic_update_time+0x4c/0x60
 file_modified+0xcc/0xd0
 ext4_buffered_write_iter+0x58/0x124
 ext4_file_write_iter+0x54/0x704
 vfs_write+0x1c0/0x308
 ksys_write+0x74/0x10c
 __arm64_sys_write+0x1c/0x28
 invoke_syscall+0x48/0x114
 el0_svc_common.constprop.0+0xc0/0xe0
 do_el0_svc+0x1c/0x28
 el0_svc+0x40/0xe4
 el0t_64_sync_handler+0x120/0x12c
 el0t_64_sync+0x194/0x198

Root cause is:

systemd-random-seed                         kworker
----------------------------------------------------------------------
___mark_inode_dirty                     inode_switch_wbs_work_fn

  spin_lock(&inode->i_lock);
  inode_attach_wb
  locked_inode_to_wb_and_lock_list
     get inode->i_wb
     spin_unlock(&inode->i_lock);
     spin_lock(&wb->list_lock)
  spin_lock(&inode->i_lock)
  inode_io_list_move_locked
  spin_unlock(&wb->list_lock)
  spin_unlock(&inode->i_lock)
                                    spin_lock(&old_wb->list_lock)
                                      inode_do_switch_wbs
                                        spin_lock(&inode->i_lock)
                                        inode->i_wb = new_wb
                                        spin_unlock(&inode->i_lock)
                                    spin_unlock(&old_wb->list_lock)
                                    wb_put_many(old_wb, nr_switched)
                                      cgwb_release
                                      old wb released
  wb_wakeup_delayed() accesses wb,
  then trigger the use-after-free
  issue

Fix this race condition by holding inode spinlock until
wb_wakeup_delayed() finished.

Signed-off-by: Jiufei Xue <[email protected]>
Link: https://lore.kernel.org/[email protected]
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
…dlock

When a user creates a dualpi2 qdisc it automatically sets a timer. This
timer will run constantly and update the qdisc's probability field.
The issue is that the timer acquires the qdisc root lock and runs in
hardirq. The qdisc root lock is also acquired in dev.c whenever a packet
arrives for this qdisc. Since the dualpi2 timer callback runs in hardirq,
it may interrupt the packet processing running in softirq. If that happens
and it runs on the same CPU, it will acquire the same lock and cause a
deadlock. The following splat shows up when running a kernel compiled with
lock debugging:

[  +0.000224] WARNING: inconsistent lock state
[  +0.000224] 6.16.0+ torvalds#10 Not tainted
[  +0.000169] --------------------------------
[  +0.000029] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[  +0.000000] ping/156 [HC0[0]:SC0[2]:HE1:SE0] takes:
[  +0.000000] ffff897841242110 (&sch->root_lock_key){?.-.}-{3:3}, at: __dev_queue_xmit+0x86d/0x1140
[  +0.000000] {IN-HARDIRQ-W} state was registered at:
[  +0.000000]   lock_acquire.part.0+0xb6/0x220
[  +0.000000]   _raw_spin_lock+0x31/0x80
[  +0.000000]   dualpi2_timer+0x6f/0x270
[  +0.000000]   __hrtimer_run_queues+0x1c5/0x360
[  +0.000000]   hrtimer_interrupt+0x115/0x260
[  +0.000000]   __sysvec_apic_timer_interrupt+0x6d/0x1a0
[  +0.000000]   sysvec_apic_timer_interrupt+0x6e/0x80
[  +0.000000]   asm_sysvec_apic_timer_interrupt+0x1a/0x20
[  +0.000000]   pv_native_safe_halt+0xf/0x20
[  +0.000000]   default_idle+0x9/0x10
[  +0.000000]   default_idle_call+0x7e/0x1e0
[  +0.000000]   do_idle+0x1e8/0x250
[  +0.000000]   cpu_startup_entry+0x29/0x30
[  +0.000000]   rest_init+0x151/0x160
[  +0.000000]   start_kernel+0x6f3/0x700
[  +0.000000]   x86_64_start_reservations+0x24/0x30
[  +0.000000]   x86_64_start_kernel+0xc8/0xd0
[  +0.000000]   common_startup_64+0x13e/0x148
[  +0.000000] irq event stamp: 6884
[  +0.000000] hardirqs last  enabled at (6883): [<ffffffffa75700b3>] neigh_resolve_output+0x223/0x270
[  +0.000000] hardirqs last disabled at (6882): [<ffffffffa7570078>] neigh_resolve_output+0x1e8/0x270
[  +0.000000] softirqs last  enabled at (6880): [<ffffffffa757006b>] neigh_resolve_output+0x1db/0x270
[  +0.000000] softirqs last disabled at (6884): [<ffffffffa755b533>] __dev_queue_xmit+0x73/0x1140
[  +0.000000]
              other info that might help us debug this:
[  +0.000000]  Possible unsafe locking scenario:

[  +0.000000]        CPU0
[  +0.000000]        ----
[  +0.000000]   lock(&sch->root_lock_key);
[  +0.000000]   <Interrupt>
[  +0.000000]     lock(&sch->root_lock_key);
[  +0.000000]
               *** DEADLOCK ***

[  +0.000000] 4 locks held by ping/156:
[  +0.000000]  #0: ffff897842332e08 (sk_lock-AF_INET){+.+.}-{0:0}, at: raw_sendmsg+0x41e/0xf40
[  +0.000000]  #1: ffffffffa816f880 (rcu_read_lock){....}-{1:3}, at: ip_output+0x2c/0x190
[  +0.000000]  #2: ffffffffa816f880 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0xad/0x950
[  +0.000000]  #3: ffffffffa816f840 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x73/0x1140

I am able to reproduce it consistently when running the following:

tc qdisc add dev lo handle 1: root dualpi2
ping -f 127.0.0.1

To fix it, make the timer run in softirq.

Fixes: 320d031 ("sched: Struct definition and parsing of dualpi2 qdisc")
Reviewed-by: Jamal Hadi Salim <[email protected]>
Signed-off-by: Victor Nogueira <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
BPF CI testing report a UAF issue:

  [   16.446633] BUG: kernel NULL pointer dereference, address: 000000000000003  0
  [   16.447134] #PF: supervisor read access in kernel mod  e
  [   16.447516] #PF: error_code(0x0000) - not-present pag  e
  [   16.447878] PGD 0 P4D   0
  [   16.448063] Oops: Oops: 0000 [#1] PREEMPT SMP NOPT  I
  [   16.448409] CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Tainted: G           OE      6.13.0-rc3-g89e8a75fda73-dirty #4  2
  [   16.449124] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODUL  E
  [   16.449502] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/201  4
  [   16.450201] Workqueue: smc_hs_wq smc_listen_wor  k
  [   16.450531] RIP: 0010:smc_listen_work+0xc02/0x159  0
  [   16.452158] RSP: 0018:ffffb5ab40053d98 EFLAGS: 0001024  6
  [   16.452526] RAX: 0000000000000001 RBX: 0000000000000002 RCX: 000000000000030  0
  [   16.452994] RDX: 0000000000000280 RSI: 00003513840053f0 RDI: 000000000000000  0
  [   16.453492] RBP: ffffa097808e3800 R08: ffffa09782dba1e0 R09: 000000000000000  5
  [   16.453987] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa0978274640  0
  [   16.454497] R13: 0000000000000000 R14: 0000000000000000 R15: ffffa09782d4092  0
  [   16.454996] FS:  0000000000000000(0000) GS:ffffa097bbc00000(0000) knlGS:000000000000000  0
  [   16.455557] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003  3
  [   16.455961] CR2: 0000000000000030 CR3: 0000000102788004 CR4: 0000000000770ef  0
  [   16.456459] PKRU: 5555555  4
  [   16.456654] Call Trace  :
  [   16.456832]  <TASK  >
  [   16.456989]  ? __die+0x23/0x7  0
  [   16.457215]  ? page_fault_oops+0x180/0x4c  0
  [   16.457508]  ? __lock_acquire+0x3e6/0x249  0
  [   16.457801]  ? exc_page_fault+0x68/0x20  0
  [   16.458080]  ? asm_exc_page_fault+0x26/0x3  0
  [   16.458389]  ? smc_listen_work+0xc02/0x159  0
  [   16.458689]  ? smc_listen_work+0xc02/0x159  0
  [   16.458987]  ? lock_is_held_type+0x8f/0x10  0
  [   16.459284]  process_one_work+0x1ea/0x6d  0
  [   16.459570]  worker_thread+0x1c3/0x38  0
  [   16.459839]  ? __pfx_worker_thread+0x10/0x1  0
  [   16.460144]  kthread+0xe0/0x11  0
  [   16.460372]  ? __pfx_kthread+0x10/0x1  0
  [   16.460640]  ret_from_fork+0x31/0x5  0
  [   16.460896]  ? __pfx_kthread+0x10/0x1  0
  [   16.461166]  ret_from_fork_asm+0x1a/0x3  0
  [   16.461453]  </TASK  >
  [   16.461616] Modules linked in: bpf_testmod(OE) [last unloaded: bpf_testmod(OE)  ]
  [   16.462134] CR2: 000000000000003  0
  [   16.462380] ---[ end trace 0000000000000000 ]---
  [   16.462710] RIP: 0010:smc_listen_work+0xc02/0x1590

The direct cause of this issue is that after smc_listen_out_connected(),
newclcsock->sk may be NULL since it will releases the smcsk. Therefore,
if the application closes the socket immediately after accept,
newclcsock->sk can be NULL. A possible execution order could be as
follows:

smc_listen_work                                 | userspace
-----------------------------------------------------------------
lock_sock(sk)                                   |
smc_listen_out_connected()                      |
| \- smc_listen_out                             |
|    | \- release_sock                          |
     | |- sk->sk_data_ready()                   |
                                                | fd = accept();
                                                | close(fd);
                                                |  \- socket->sk = NULL;
/* newclcsock->sk is NULL now */
SMC_STAT_SERV_SUCC_INC(sock_net(newclcsock->sk))

Since smc_listen_out_connected() will not fail, simply swapping the order
of the code can easily fix this issue.

Fixes: 3b2dec2 ("net/smc: restructure client and server code in af_smc")
Signed-off-by: D. Wythe <[email protected]>
Reviewed-by: Guangguan Wang <[email protected]>
Reviewed-by: Alexandra Winter <[email protected]>
Reviewed-by: Dust Li <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
Receiving HSR frame with insufficient space to hold HSR tag in the skb
can result in a crash (kernel BUG):

[   45.390915] skbuff: skb_under_panic: text:ffffffff86f32cac len:26 put:14 head:ffff888042418000 data:ffff888042417ff4 tail:0xe end:0x180 dev:bridge_slave_1
[   45.392559] ------------[ cut here ]------------
[   45.392912] kernel BUG at net/core/skbuff.c:211!
[   45.393276] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[   45.393809] CPU: 1 UID: 0 PID: 2496 Comm: reproducer Not tainted 6.15.0 torvalds#12 PREEMPT(undef)
[   45.394433] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   45.395273] RIP: 0010:skb_panic+0x15b/0x1d0

<snip registers, remove unreliable trace>

[   45.402911] Call Trace:
[   45.403105]  <IRQ>
[   45.404470]  skb_push+0xcd/0xf0
[   45.404726]  br_dev_queue_push_xmit+0x7c/0x6c0
[   45.406513]  br_forward_finish+0x128/0x260
[   45.408483]  __br_forward+0x42d/0x590
[   45.409464]  maybe_deliver+0x2eb/0x420
[   45.409763]  br_flood+0x174/0x4a0
[   45.410030]  br_handle_frame_finish+0xc7c/0x1bc0
[   45.411618]  br_handle_frame+0xac3/0x1230
[   45.413674]  __netif_receive_skb_core.constprop.0+0x808/0x3df0
[   45.422966]  __netif_receive_skb_one_core+0xb4/0x1f0
[   45.424478]  __netif_receive_skb+0x22/0x170
[   45.424806]  process_backlog+0x242/0x6d0
[   45.425116]  __napi_poll+0xbb/0x630
[   45.425394]  net_rx_action+0x4d1/0xcc0
[   45.427613]  handle_softirqs+0x1a4/0x580
[   45.427926]  do_softirq+0x74/0x90
[   45.428196]  </IRQ>

This issue was found by syzkaller.

The panic happens in br_dev_queue_push_xmit() once it receives a
corrupted skb with ETH header already pushed in linear data. When it
attempts the skb_push() call, there's not enough headroom and
skb_push() panics.

The corrupted skb is put on the queue by HSR layer, which makes a
sequence of unintended transformations when it receives a specific
corrupted HSR frame (with incomplete TAG).

Fix it by dropping and consuming frames that are not long enough to
contain both ethernet and hsr headers.

Alternative fix would be to check for enough headroom before skb_push()
in br_dev_queue_push_xmit().

In the reproducer, this is injected via AF_PACKET, but I don't easily
see why it couldn't be sent over the wire from adjacent network.

Further Details:

In the reproducer, the following network interface chain is set up:

┌────────────────┐   ┌────────────────┐
│ veth0_to_hsr   ├───┤  hsr_slave0    ┼───┐
└────────────────┘   └────────────────┘   │
                                          │ ┌──────┐
                                          ├─┤ hsr0 ├───┐
                                          │ └──────┘   │
┌────────────────┐   ┌────────────────┐   │            │┌────────┐
│ veth1_to_hsr   ┼───┤  hsr_slave1    ├───┘            └┤        │
└────────────────┘   └────────────────┘                ┌┼ bridge │
                                                       ││        │
                                                       │└────────┘
                                                       │
                                        ┌───────┐      │
                                        │  ...  ├──────┘
                                        └───────┘

To trigger the events leading up to crash, reproducer sends a corrupted
HSR frame with incomplete TAG, via AF_PACKET socket on 'veth0_to_hsr'.

The first HSR-layer function to process this frame is
hsr_handle_frame(). It and then checks if the
protocol is ETH_P_PRP or ETH_P_HSR. If it is, it calls
skb_set_network_header(skb, ETH_HLEN + HSR_HLEN), without checking that
the skb is long enough. For the crashing frame it is not, and hence the
skb->network_header and skb->mac_len fields are set incorrectly,
pointing after the end of the linear buffer.

I will call this a BUG#1 and it is what is addressed by this patch. In
the crashing scenario before the fix, the skb continues to go down the
hsr path as follows.

hsr_handle_frame() then calls this sequence
hsr_forward_skb()
  fill_frame_info()
    hsr->proto_ops->fill_frame_info()
      hsr_fill_frame_info()

hsr_fill_frame_info() contains a check that intends to check whether the
skb actually contains the HSR header. But the check relies on the
skb->mac_len field which was erroneously setup due to BUG#1, so the
check passes and the execution continues  back in the hsr_forward_skb():

hsr_forward_skb()
  hsr_forward_do()
    hsr->proto_ops->get_untagged_frame()
      hsr_get_untagged_frame()
        create_stripped_skb_hsr()

In create_stripped_skb_hsr(), a copy of the skb is created and is
further corrupted by operation that attempts to strip the HSR tag in a
call to __pskb_copy().

The skb enters create_stripped_skb_hsr() with ethernet header pushed in
linear buffer. The skb_pull(skb_in, HSR_HLEN) thus pulls 6 bytes of
ethernet header into the headroom, creating skb_in with a headroom of
size 8. The subsequent __pskb_copy() then creates an skb with headroom
of just 2 and skb->len of just 12, this is how it looks after the copy:

gdb) p skb->len
$10 = 12
(gdb) p skb->data
$11 = (unsigned char *) 0xffff888041e45382 "\252\252\252\252\252!\210\373",
(gdb) p skb->head
$12 = (unsigned char *) 0xffff888041e45380 ""

It seems create_stripped_skb_hsr() assumes that ETH header is pulled
in the headroom when it's entered, because it just pulls HSR header on
top. But that is not the case in our code-path and we end up with the
corrupted skb instead. I will call this BUG#2

*I got confused here because it seems that under no conditions can
create_stripped_skb_hsr() work well, the assumption it makes is not true
during the processing of hsr frames - since the skb_push() in
hsr_handle_frame to skb_pull in hsr_deliver_master(). I wonder whether I
missed something here.*

Next, the execution arrives in hsr_deliver_master(). It calls
skb_pull(ETH_HLEN), which just returns NULL - the SKB does not have
enough space for the pull (as it only has 12 bytes in total at this
point).

*The skb_pull() here further suggests that ethernet header is meant
to be pushed through the whole hsr processing and
create_stripped_skb_hsr() should pull it before doing the HSR header
pull.*

hsr_deliver_master() then puts the corrupted skb on the queue, it is
then picked up from there by bridge frame handling layer and finally
lands in br_dev_queue_push_xmit where it panics.

Cc: [email protected]
Fixes: 48b491a ("net: hsr: fix mac_len checks")
Reported-by: [email protected]
Signed-off-by: Jakub Acs <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
The mm/debug_vm_pagetable test allocates manually page table entries for
the tests it runs, using also its manually allocated mm_struct.  That in
itself is ok, but when it exits, at destroy_args() it fails to clear those
entries with the *_clear functions.

The problem is that leaves stale entries.  If another process allocates an
mm_struct with a pgd at the same address, it may end up running into the
stale entry.  This is happening in practice on a debug kernel with
CONFIG_DEBUG_VM_PGTABLE=y, for example this is the output with some extra
debugging I added (it prints a warning trace if pgtables_bytes goes
negative, in addition to the warning at check_mm() function):

[    2.539353] debug_vm_pgtable: [get_random_vaddr         ]: random_vaddr is 0x7ea247140000
[    2.539366] kmem_cache info
[    2.539374] kmem_cachep 0x000000002ce82385 - freelist 0x0000000000000000 - offset 0x508
[    2.539447] debug_vm_pgtable: [init_args                ]: args->mm is 0x000000002267cc9e
(...)
[    2.552800] WARNING: CPU: 5 PID: 116 at include/linux/mm.h:2841 free_pud_range+0x8bc/0x8d0
[    2.552816] Modules linked in:
[    2.552843] CPU: 5 UID: 0 PID: 116 Comm: modprobe Not tainted 6.12.0-105.debug_vm2.el10.ppc64le+debug #1 VOLUNTARY
[    2.552859] Hardware name: IBM,9009-41A POWER9 (architected) 0x4e0202 0xf000005 of:IBM,FW910.00 (VL910_062) hv:phyp pSeries
[    2.552872] NIP:  c0000000007eef3c LR: c0000000007eef30 CTR: c0000000003d8c90
[    2.552885] REGS: c0000000622e73b0 TRAP: 0700   Not tainted  (6.12.0-105.debug_vm2.el10.ppc64le+debug)
[    2.552899] MSR:  800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 24002822  XER: 0000000a
[    2.552954] CFAR: c0000000008f03f0 IRQMASK: 0
[    2.552954] GPR00: c0000000007eef30 c0000000622e7650 c000000002b1ac00 0000000000000001
[    2.552954] GPR04: 0000000000000008 0000000000000000 c0000000007eef30 ffffffffffffffff
[    2.552954] GPR08: 00000000ffff00f5 0000000000000001 0000000000000048 0000000000004000
[    2.552954] GPR12: 00000003fa440000 c000000017ffa300 c0000000051d9f80 ffffffffffffffdb
[    2.552954] GPR16: 0000000000000000 0000000000000008 000000000000000a 60000000000000e0
[    2.552954] GPR20: 4080000000000000 c0000000113af038 00007fffcf130000 0000700000000000
[    2.552954] GPR24: c000000062a6a000 0000000000000001 8000000062a68000 0000000000000001
[    2.552954] GPR28: 000000000000000a c000000062ebc600 0000000000002000 c000000062ebc760
[    2.553170] NIP [c0000000007eef3c] free_pud_range+0x8bc/0x8d0
[    2.553185] LR [c0000000007eef30] free_pud_range+0x8b0/0x8d0
[    2.553199] Call Trace:
[    2.553207] [c0000000622e7650] [c0000000007eef30] free_pud_range+0x8b0/0x8d0 (unreliable)
[    2.553229] [c0000000622e7750] [c0000000007f40b4] free_pgd_range+0x284/0x3b0
[    2.553248] [c0000000622e7800] [c0000000007f4630] free_pgtables+0x450/0x570
[    2.553274] [c0000000622e78e0] [c0000000008161c0] exit_mmap+0x250/0x650
[    2.553292] [c0000000622e7a30] [c0000000001b95b8] __mmput+0x98/0x290
[    2.558344] [c0000000622e7a80] [c0000000001d1018] exit_mm+0x118/0x1b0
[    2.558361] [c0000000622e7ac0] [c0000000001d141c] do_exit+0x2ec/0x870
[    2.558376] [c0000000622e7b60] [c0000000001d1ca8] do_group_exit+0x88/0x150
[    2.558391] [c0000000622e7bb0] [c0000000001d1db8] sys_exit_group+0x48/0x50
[    2.558407] [c0000000622e7be0] [c00000000003d810] system_call_exception+0x1e0/0x4c0
[    2.558423] [c0000000622e7e50] [c00000000000d05c] system_call_vectored_common+0x15c/0x2ec
(...)
[    2.558892] ---[ end trace 0000000000000000 ]---
[    2.559022] BUG: Bad rss-counter state mm:000000002267cc9e type:MM_ANONPAGES val:1
[    2.559037] BUG: non-zero pgtables_bytes on freeing mm: -6144

Here the modprobe process ended up with an allocated mm_struct from the
mm_struct slab that was used before by the debug_vm_pgtable test.  That is
not a problem, since the mm_struct is initialized again etc., however, if
it ends up using the same pgd table, it bumps into the old stale entry
when clearing/freeing the page table entries, so it tries to free an entry
already gone (that one which was allocated by the debug_vm_pgtable test),
which also explains the negative pgtables_bytes since it's accounting for
not allocated entries in the current process.

As far as I looked pgd_{alloc,free} etc.  does not clear entries, and
clearing of the entries is explicitly done in the free_pgtables->
free_pgd_range->free_p4d_range->free_pud_range->free_pmd_range->
free_pte_range path.  However, the debug_vm_pgtable test does not call
free_pgtables, since it allocates mm_struct and entries manually for its
test and eg.  not goes through page faults.  So it also should clear
manually the entries before exit at destroy_args().

This problem was noticed on a reboot X number of times test being done on
a powerpc host, with a debug kernel with CONFIG_DEBUG_VM_PGTABLE enabled. 
Depends on the system, but on a 100 times reboot loop the problem could
manifest once or twice, if a process ends up getting the right mm->pgd
entry with the stale entries used by mm/debug_vm_pagetable.  After using
this patch, I couldn't reproduce/experience the problems anymore.  I was
able to reproduce the problem as well on latest upstream kernel (6.16).

I also modified destroy_args() to use mmput() instead of mmdrop(), there
is no reason to hold mm_users reference and not release the mm_struct
entirely, and in the output above with my debugging prints I already had
patched it to use mmput, it did not fix the problem, but helped in the
debugging as well.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 3c9b84f ("mm/debug_vm_pgtable: introduce struct pgtable_debug_args")
Signed-off-by: Herton R. Krzesinski <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Gavin Shan <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
Commit 3c7ac40 ("scsi: ufs: core: Delegate the interrupt service
routine to a threaded IRQ handler") introduced an IRQ lock inversion
issue. Fix this lock inversion by changing the spin_lock_irq() calls into
spin_lock_irqsave() calls in code that can be called either from
interrupt context or from thread context. This patch fixes the following
lockdep complaint:

WARNING: possible irq lock inversion dependency detected
6.12.30-android16-5-maybe-dirty-4k #1 Tainted: G        W  OE
--------------------------------------------------------
kworker/u28:0/12 just changed the state of lock:
ffffff881e29dd60 (&hba->clk_gating.lock){-...}-{2:2}, at: ufshcd_release_scsi_cmd+0x60/0x110
but this lock took another, HARDIRQ-unsafe lock in the past:
 (shost->host_lock){+.+.}-{2:2}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(shost->host_lock);
                               local_irq_disable();
                               lock(&hba->clk_gating.lock);
                               lock(shost->host_lock);
  <Interrupt>
    lock(&hba->clk_gating.lock);

 *** DEADLOCK ***

4 locks held by kworker/u28:0/12:
 #0: ffffff8800ac6158 ((wq_completion)async){+.+.}-{0:0}, at: process_one_work+0x1bc/0x65c
 #1: ffffffc085c93d70 ((work_completion)(&entry->work)){+.+.}-{0:0}, at: process_one_work+0x1e4/0x65c
 #2: ffffff881e29c0e0 (&shost->scan_mutex){+.+.}-{3:3}, at: __scsi_add_device+0x74/0x120
 #3: ffffff881960ea00 (&hwq->cq_lock){-...}-{2:2}, at: ufshcd_mcq_poll_cqe_lock+0x28/0x104

the shortest dependencies between 2nd lock and 1st lock:
 -> (shost->host_lock){+.+.}-{2:2} {
    HARDIRQ-ON-W at:
                      lock_acquire+0x134/0x2b4
                      _raw_spin_lock+0x48/0x64
                      ufshcd_sl_intr+0x4c/0xa08
                      ufshcd_threaded_intr+0x70/0x12c
                      irq_thread_fn+0x48/0xa8
                      irq_thread+0x130/0x1ec
                      kthread+0x110/0x134
                      ret_from_fork+0x10/0x20
    SOFTIRQ-ON-W at:
                      lock_acquire+0x134/0x2b4
                      _raw_spin_lock+0x48/0x64
                      ufshcd_sl_intr+0x4c/0xa08
                      ufshcd_threaded_intr+0x70/0x12c
                      irq_thread_fn+0x48/0xa8
                      irq_thread+0x130/0x1ec
                      kthread+0x110/0x134
                      ret_from_fork+0x10/0x20
    INITIAL USE at:
                     lock_acquire+0x134/0x2b4
                     _raw_spin_lock+0x48/0x64
                     ufshcd_sl_intr+0x4c/0xa08
                     ufshcd_threaded_intr+0x70/0x12c
                     irq_thread_fn+0x48/0xa8
                     irq_thread+0x130/0x1ec
                     kthread+0x110/0x134
                     ret_from_fork+0x10/0x20
  }
  ... key      at: [<ffffffc085ba1a98>] scsi_host_alloc.__key+0x0/0x10
  ... acquired at:
   _raw_spin_lock_irqsave+0x5c/0x80
   __ufshcd_release+0x78/0x118
   ufshcd_send_uic_cmd+0xe4/0x118
   ufshcd_dme_set_attr+0x88/0x1c8
   ufs_google_phy_initialization+0x68/0x418 [ufs]
   ufs_google_link_startup_notify+0x78/0x27c [ufs]
   ufshcd_link_startup+0x84/0x720
   ufshcd_init+0xf3c/0x1330
   ufshcd_pltfrm_init+0x728/0x7d8
   ufs_google_probe+0x30/0x84 [ufs]
   platform_probe+0xa0/0xe0
   really_probe+0x114/0x454
   __driver_probe_device+0xa4/0x160
   driver_probe_device+0x44/0x23c
   __driver_attach_async_helper+0x60/0xd4
   async_run_entry_fn+0x4c/0x17c
   process_one_work+0x26c/0x65c
   worker_thread+0x33c/0x498
   kthread+0x110/0x134
   ret_from_fork+0x10/0x20

-> (&hba->clk_gating.lock){-...}-{2:2} {
   IN-HARDIRQ-W at:
                    lock_acquire+0x134/0x2b4
                    _raw_spin_lock_irqsave+0x5c/0x80
                    ufshcd_release_scsi_cmd+0x60/0x110
                    ufshcd_compl_one_cqe+0x2c0/0x3f4
                    ufshcd_mcq_poll_cqe_lock+0xb0/0x104
                    ufs_google_mcq_intr+0x80/0xa0 [ufs]
                    __handle_irq_event_percpu+0x104/0x32c
                    handle_irq_event+0x40/0x9c
                    handle_fasteoi_irq+0x170/0x2e8
                    generic_handle_domain_irq+0x58/0x80
                    gic_handle_irq+0x48/0x104
                    call_on_irq_stack+0x3c/0x50
                    do_interrupt_handler+0x7c/0xd8
                    el1_interrupt+0x34/0x58
                    el1h_64_irq_handler+0x18/0x24
                    el1h_64_irq+0x68/0x6c
                    _raw_spin_unlock_irqrestore+0x3c/0x6c
                    debug_object_assert_init+0x16c/0x21c
                    __mod_timer+0x4c/0x48c
                    schedule_timeout+0xd4/0x16c
                    io_schedule_timeout+0x48/0x70
                    do_wait_for_common+0x100/0x194
                    wait_for_completion_io_timeout+0x48/0x6c
                    blk_execute_rq+0x124/0x17c
                    scsi_execute_cmd+0x18c/0x3f8
                    scsi_probe_and_add_lun+0x204/0xd74
                    __scsi_add_device+0xbc/0x120
                    ufshcd_async_scan+0x80/0x3c0
                    async_run_entry_fn+0x4c/0x17c
                    process_one_work+0x26c/0x65c
                    worker_thread+0x33c/0x498
                    kthread+0x110/0x134
                    ret_from_fork+0x10/0x20
   INITIAL USE at:
                   lock_acquire+0x134/0x2b4
                   _raw_spin_lock_irqsave+0x5c/0x80
                   ufshcd_hold+0x34/0x14c
                   ufshcd_send_uic_cmd+0x28/0x118
                   ufshcd_dme_set_attr+0x88/0x1c8
                   ufs_google_phy_initialization+0x68/0x418 [ufs]
                   ufs_google_link_startup_notify+0x78/0x27c [ufs]
                   ufshcd_link_startup+0x84/0x720
                   ufshcd_init+0xf3c/0x1330
                   ufshcd_pltfrm_init+0x728/0x7d8
                   ufs_google_probe+0x30/0x84 [ufs]
                   platform_probe+0xa0/0xe0
                   really_probe+0x114/0x454
                   __driver_probe_device+0xa4/0x160
                   driver_probe_device+0x44/0x23c
                   __driver_attach_async_helper+0x60/0xd4
                   async_run_entry_fn+0x4c/0x17c
                   process_one_work+0x26c/0x65c
                   worker_thread+0x33c/0x498
                   kthread+0x110/0x134
                   ret_from_fork+0x10/0x20
 }
 ... key      at: [<ffffffc085ba6fe8>] ufshcd_init.__key+0x0/0x10
 ... acquired at:
   mark_lock+0x1c4/0x224
   __lock_acquire+0x438/0x2e1c
   lock_acquire+0x134/0x2b4
   _raw_spin_lock_irqsave+0x5c/0x80
   ufshcd_release_scsi_cmd+0x60/0x110
   ufshcd_compl_one_cqe+0x2c0/0x3f4
   ufshcd_mcq_poll_cqe_lock+0xb0/0x104
   ufs_google_mcq_intr+0x80/0xa0 [ufs]
   __handle_irq_event_percpu+0x104/0x32c
   handle_irq_event+0x40/0x9c
   handle_fasteoi_irq+0x170/0x2e8
   generic_handle_domain_irq+0x58/0x80
   gic_handle_irq+0x48/0x104
   call_on_irq_stack+0x3c/0x50
   do_interrupt_handler+0x7c/0xd8
   el1_interrupt+0x34/0x58
   el1h_64_irq_handler+0x18/0x24
   el1h_64_irq+0x68/0x6c
   _raw_spin_unlock_irqrestore+0x3c/0x6c
   debug_object_assert_init+0x16c/0x21c
   __mod_timer+0x4c/0x48c
   schedule_timeout+0xd4/0x16c
   io_schedule_timeout+0x48/0x70
   do_wait_for_common+0x100/0x194
   wait_for_completion_io_timeout+0x48/0x6c
   blk_execute_rq+0x124/0x17c
   scsi_execute_cmd+0x18c/0x3f8
   scsi_probe_and_add_lun+0x204/0xd74
   __scsi_add_device+0xbc/0x120
   ufshcd_async_scan+0x80/0x3c0
   async_run_entry_fn+0x4c/0x17c
   process_one_work+0x26c/0x65c
   worker_thread+0x33c/0x498
   kthread+0x110/0x134
   ret_from_fork+0x10/0x20

stack backtrace:
CPU: 6 UID: 0 PID: 12 Comm: kworker/u28:0 Tainted: G        W  OE      6.12.30-android16-5-maybe-dirty-4k #1 ccd4020fe444bdf629efc3b86df6be920b8df7d0
Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: Spacecraft board based on MALIBU (DT)
Workqueue: async async_run_entry_fn
Call trace:
 dump_backtrace+0xfc/0x17c
 show_stack+0x18/0x28
 dump_stack_lvl+0x40/0xa0
 dump_stack+0x18/0x24
 print_irq_inversion_bug+0x2fc/0x304
 mark_lock_irq+0x388/0x4fc
 mark_lock+0x1c4/0x224
 __lock_acquire+0x438/0x2e1c
 lock_acquire+0x134/0x2b4
 _raw_spin_lock_irqsave+0x5c/0x80
 ufshcd_release_scsi_cmd+0x60/0x110
 ufshcd_compl_one_cqe+0x2c0/0x3f4
 ufshcd_mcq_poll_cqe_lock+0xb0/0x104
 ufs_google_mcq_intr+0x80/0xa0 [ufs dd6f385554e109da094ab91d5f7be18625a2222a]
 __handle_irq_event_percpu+0x104/0x32c
 handle_irq_event+0x40/0x9c
 handle_fasteoi_irq+0x170/0x2e8
 generic_handle_domain_irq+0x58/0x80
 gic_handle_irq+0x48/0x104
 call_on_irq_stack+0x3c/0x50
 do_interrupt_handler+0x7c/0xd8
 el1_interrupt+0x34/0x58
 el1h_64_irq_handler+0x18/0x24
 el1h_64_irq+0x68/0x6c
 _raw_spin_unlock_irqrestore+0x3c/0x6c
 debug_object_assert_init+0x16c/0x21c
 __mod_timer+0x4c/0x48c
 schedule_timeout+0xd4/0x16c
 io_schedule_timeout+0x48/0x70
 do_wait_for_common+0x100/0x194
 wait_for_completion_io_timeout+0x48/0x6c
 blk_execute_rq+0x124/0x17c
 scsi_execute_cmd+0x18c/0x3f8
 scsi_probe_and_add_lun+0x204/0xd74
 __scsi_add_device+0xbc/0x120
 ufshcd_async_scan+0x80/0x3c0
 async_run_entry_fn+0x4c/0x17c
 process_one_work+0x26c/0x65c
 worker_thread+0x33c/0x498
 kthread+0x110/0x134
 ret_from_fork+0x10/0x20

Cc: Neil Armstrong <[email protected]>
Cc: André Draszik <[email protected]>
Reviewed-by: Peter Wang <[email protected]>
Fixes: 3c7ac40 ("scsi: ufs: core: Delegate the interrupt service routine to a threaded IRQ handler")
Signed-off-by: Bart Van Assche <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
These iterations require the read lock, otherwise RCU
lockdep will splat:

=============================
WARNING: suspicious RCU usage
6.17.0-rc3-00014-g31419c045d64 #6 Tainted: G           O
-----------------------------
drivers/base/power/main.c:1333 RCU-list traversed in non-reader section!!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
5 locks held by rtcwake/547:
 #0: 00000000643ab418 (sb_writers#6){.+.+}-{0:0}, at: file_start_write+0x2b/0x3a
 #1: 0000000067a0ca88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x181/0x24b
 #2: 00000000631eac40 (kn->active#3){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x191/0x24b
 #3: 00000000609a1308 (system_transition_mutex){+.+.}-{4:4}, at: pm_suspend+0xaf/0x30b
 #4: 0000000060c0fdb0 (device_links_srcu){.+.+}-{0:0}, at: device_links_read_lock+0x75/0x98

stack backtrace:
CPU: 0 UID: 0 PID: 547 Comm: rtcwake Tainted: G           O        6.17.0-rc3-00014-g31419c045d64 #6 VOLUNTARY
Tainted: [O]=OOT_MODULE
Stack:
 223721b3a80 6089eac6 00000001 00000001
 ffffff00 6089eac6 00000535 6086e528
 721b3ac0 6003c294 00000000 60031fc0
Call Trace:
 [<600407ed>] show_stack+0x10e/0x127
 [<6003c294>] dump_stack_lvl+0x77/0xc6
 [<6003c2fd>] dump_stack+0x1a/0x20
 [<600bc2f8>] lockdep_rcu_suspicious+0x116/0x13e
 [<603d8ea1>] dpm_async_suspend_superior+0x117/0x17e
 [<603d980f>] device_suspend+0x528/0x541
 [<603da24b>] dpm_suspend+0x1a2/0x267
 [<603da837>] dpm_suspend_start+0x5d/0x72
 [<600ca0c9>] suspend_devices_and_enter+0xab/0x736
 [...]

Add the fourth argument to the iteration to annotate
this and avoid the splat.

Fixes: 0679963 ("PM: sleep: Make async suspend handle suppliers like parents")
Fixes: ed18738 ("PM: sleep: Make async resume handle consumers like children")
Signed-off-by: Johannes Berg <[email protected]>
Link: https://patch.msgid.link/20250826134348.aba79f6e6299.I9ecf55da46ccf33778f2c018a82e1819d815b348@changeid
Signed-off-by: Rafael J. Wysocki <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
syzbot reported the splat below. [0]

When atmtcp_v_open() or atmtcp_v_close() is called via connect()
or close(), atmtcp_send_control() is called to send an in-kernel
special message.

The message has ATMTCP_HDR_MAGIC in atmtcp_control.hdr.length.
Also, a pointer of struct atm_vcc is set to atmtcp_control.vcc.

The notable thing is struct atmtcp_control is uAPI but has a
space for an in-kernel pointer.

  struct atmtcp_control {
  	struct atmtcp_hdr hdr;	/* must be first */
  ...
  	atm_kptr_t vcc;		/* both directions */
  ...
  } __ATM_API_ALIGN;

  typedef struct { unsigned char _[8]; } __ATM_API_ALIGN atm_kptr_t;

The special message is processed in atmtcp_recv_control() called
from atmtcp_c_send().

atmtcp_c_send() is vcc->dev->ops->send() and called from 2 paths:

  1. .ndo_start_xmit() (vcc->send() == atm_send_aal0())
  2. vcc_sendmsg()

The problem is sendmsg() does not validate the message length and
userspace can abuse atmtcp_recv_control() to overwrite any kptr
by atmtcp_control.

Let's add a new ->pre_send() hook to validate messages from sendmsg().

[0]:
Oops: general protection fault, probably for non-canonical address 0xdffffc00200000ab: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x0000000100000558-0x000000010000055f]
CPU: 0 UID: 0 PID: 5865 Comm: syz-executor331 Not tainted 6.17.0-rc1-syzkaller-00215-gbab3ce404553 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:atmtcp_recv_control drivers/atm/atmtcp.c:93 [inline]
RIP: 0010:atmtcp_c_send+0x1da/0x950 drivers/atm/atmtcp.c:297
Code: 4d 8d 75 1a 4c 89 f0 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 15 06 00 00 41 0f b7 1e 4d 8d b7 60 05 00 00 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 13 06 00 00 66 41 89 1e 4d 8d 75 1c 4c
RSP: 0018:ffffc90003f5f810 EFLAGS: 00010203
RAX: 00000000200000ab RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88802a510000 RSI: 00000000ffffffff RDI: ffff888030a6068c
RBP: ffff88802699fb40 R08: ffff888030a606eb R09: 1ffff1100614c0dd
R10: dffffc0000000000 R11: ffffffff8718fc40 R12: dffffc0000000000
R13: ffff888030a60680 R14: 000000010000055f R15: 00000000ffffffff
FS:  00007f8d7e9236c0(0000) GS:ffff888125c1c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045ad50 CR3: 0000000075bde000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 vcc_sendmsg+0xa10/0xc60 net/atm/common.c:645
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:729
 ____sys_sendmsg+0x505/0x830 net/socket.c:2614
 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
 __sys_sendmsg net/socket.c:2700 [inline]
 __do_sys_sendmsg net/socket.c:2705 [inline]
 __se_sys_sendmsg net/socket.c:2703 [inline]
 __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8d7e96a4a9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8d7e923198 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8d7e9f4308 RCX: 00007f8d7e96a4a9
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000005
RBP: 00007f8d7e9f4300 R08: 65732f636f72702f R09: 65732f636f72702f
R10: 65732f636f72702f R11: 0000000000000246 R12: 00007f8d7e9c10ac
R13: 00007f8d7e9231a0 R14: 0000200000000200 R15: 0000200000000250
 </TASK>
Modules linked in:

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: [email protected]
Closes: https://lore.kernel.org/netdev/[email protected]/
Tested-by: [email protected]
Signed-off-by: Kuniyuki Iwashima <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
If preparing a write bio fails then blk_zone_wplug_bio_work() calls
bio_endio() with zwplug->lock held. If a device mapper driver is stacked
on top of the zoned block device then this results in nested locking of
zwplug->lock. The resulting lockdep complaint is a false positive
because this is nested locking and not recursive locking. Suppress this
false positive by calling blk_zone_wplug_bio_io_error() without holding
zwplug->lock. This is safe because no code in
blk_zone_wplug_bio_io_error() depends on zwplug->lock being held. This
patch suppresses the following lockdep complaint:

WARNING: possible recursive locking detected
--------------------------------------------
kworker/3:0H/46 is trying to acquire lock:
ffffff882968b830 (&zwplug->lock){-...}-{2:2}, at: blk_zone_write_plug_bio_endio+0x64/0x1f0

but task is already holding lock:
ffffff88315bc230 (&zwplug->lock){-...}-{2:2}, at: blk_zone_wplug_bio_work+0x8c/0x48c

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&zwplug->lock);
  lock(&zwplug->lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by kworker/3:0H/46:
 #0: ffffff8809486758 ((wq_completion)sdd_zwplugs){+.+.}-{0:0}, at: process_one_work+0x1bc/0x65c
 #1: ffffffc085de3d70 ((work_completion)(&zwplug->bio_work)){+.+.}-{0:0}, at: process_one_work+0x1e4/0x65c
 #2: ffffff88315bc230 (&zwplug->lock){-...}-{2:2}, at: blk_zone_wplug_bio_work+0x8c/0x48c

stack backtrace:
CPU: 3 UID: 0 PID: 46 Comm: kworker/3:0H Tainted: G        W  OE      6.12.38-android16-5-maybe-dirty-4k #1 8b362b6f76e3645a58cd27d86982bce10d150025
Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: Spacecraft board based on MALIBU (DT)
Workqueue: sdd_zwplugs blk_zone_wplug_bio_work
Call trace:
 dump_backtrace+0xfc/0x17c
 show_stack+0x18/0x28
 dump_stack_lvl+0x40/0xa0
 dump_stack+0x18/0x24
 print_deadlock_bug+0x38c/0x398
 __lock_acquire+0x13e8/0x2e1c
 lock_acquire+0x134/0x2b4
 _raw_spin_lock_irqsave+0x5c/0x80
 blk_zone_write_plug_bio_endio+0x64/0x1f0
 bio_endio+0x9c/0x240
 __dm_io_complete+0x214/0x260
 clone_endio+0xe8/0x214
 bio_endio+0x218/0x240
 blk_zone_wplug_bio_work+0x204/0x48c
 process_one_work+0x26c/0x65c
 worker_thread+0x33c/0x498
 kthread+0x110/0x134
 ret_from_fork+0x10/0x20

Cc: [email protected]
Cc: Damien Le Moal <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Fixes: dd291d7 ("block: Introduce zone write plugging")
Signed-off-by: Bart Van Assche <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
 into HEAD

KVM/riscv fixes for 6.17, take #1

- Fix pte settings within kvm_riscv_gstage_ioremap()
- Fix comments in kvm_riscv_check_vcpu_requests()
- Fix stack overrun when setting vlenb via ONE_REG
l1k pushed a commit that referenced this pull request Oct 4, 2025
commit c652887 ("KVM: arm64: vgic-v3: Allow userspace to write
GICD_TYPER2.nASSGIcap") makes the allocation of vPEs depend on nASSGIcap
for GICv4.1 hosts. While the vGIC v4 initialization and teardown is
handled correctly, it erroneously attempts to establish a vLPI mapping
to a VM that has no vPEs allocated:

  Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a8
   Mem abort info:
     ESR = 0x0000000096000044
     EC = 0x25: DABT (current EL), IL = 32 bits
     SET = 0, FnV = 0
     EA = 0, S1PTW = 0
     FSC = 0x04: level 0 translation fault
   Data abort info:
     ISV = 0, ISS = 0x00000044, ISS2 = 0x00000000
     CM = 0, WnR = 1, TnD = 0, TagAccess = 0
     GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
   user pgtable: 4k pages, 48-bit VAs, pgdp=00000073a453b000
   [00000000000000a8] pgd=0000000000000000, p4d=0000000000000000
   Internal error: Oops: 0000000096000044 [#1] SMP
   pstate: 23400009 (nzCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
   pc : its_irq_set_vcpu_affinity+0x58c/0x95c
   lr : its_irq_set_vcpu_affinity+0x1e0/0x95c
   sp : ffff8001029bb9e0
   pmr_save: 00000060
   x29: ffff8001029bba20 x28: ffff0001ca5e28c0 x27: 0000000000000000
   x26: 0000000000000000 x25: ffff00019eee9f80 x24: ffff0001992b3f00
   x23: ffff8001029bbab8 x22: ffff00001159fb80 x21: 00000000000024a7
   x20: 00000000000024a7 x19: ffff00019eee9fb4 x18: 0000000000000494
   x17: 000000000000000e x16: 0000000000000494 x15: 0000000000000002
   x14: ffff0001a7f34600 x13: ffffccaad1203000 x12: 0000000000000018
   x11: ffff000011991000 x10: 0000000000000000 x9 : 00000000000000a2
   x8 : 00000000000020a8 x7 : 0000000000000000 x6 : 000000000000003f
   x5 : 0000000000000040 x4 : 0000000000000000 x3 : 0000000000000004
   x2 : 0000000000000000 x1 : ffff8001029bbab8 x0 : 00000000000000a8
   Call trace:
    its_irq_set_vcpu_affinity+0x58c/0x95c
    irq_set_vcpu_affinity+0x74/0xc8
    its_map_vlpi+0x4c/0x94
    kvm_vgic_v4_set_forwarding+0x134/0x298
    kvm_arch_irq_bypass_add_producer+0x28/0x34
    irq_bypass_register_producer+0xf8/0x1d8
    vfio_msi_set_vector_signal+0x2c8/0x308
    vfio_pci_set_msi_trigger+0x198/0x2d4
    vfio_pci_set_irqs_ioctl+0xf0/0x104
    vfio_pci_core_ioctl+0x6ac/0xc5c
    vfio_device_fops_unl_ioctl+0x128/0x370
    __arm64_sys_ioctl+0x98/0xd0
    el0_svc_common+0xd8/0x1d8
    do_el0_svc+0x28/0x34
    el0_svc+0x40/0xb8
    el0t_64_sync_handler+0x70/0xbc
    el0t_64_sync+0x1a8/0x1ac
   Code: 321f0129 f940094a 8b08014 d1400900 (39000009)
   ---[ end trace 0000000000000000 ]---

Fix it by moving the GICv4.1 special-casing to
vgic_supports_direct_msis(), returning false if the user explicitly
disabled nASSGIcap for the VM.

Fixes: c652887 ("KVM: arm64: vgic-v3: Allow userspace to write GICD_TYPER2.nASSGIcap")
Suggested-by: Oliver Upton <[email protected]>
Signed-off-by: Raghavendra Rao Ananta <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Oliver Upton <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
In gicv5_irs_of_init_affinity() a WARN_ON() is triggered if:

 1) a phandle in the "cpus" property does not correspond to a valid OF
    node
 2  a CPU logical id does not exist for a given OF cpu_node

#1 is a firmware bug and should be reported as such but does not warrant a
   WARN_ON() backtrace.

#2 is not necessarily an error condition (eg a kernel can be booted with
   nr_cpus=X limiting the number of cores artificially) and therefore there
   is no reason to clutter the kernel log with WARN_ON() output when the
   condition is hit.

Rework the IRS affinity parsing code to remove undue WARN_ON()s thus
making it less noisy.

Signed-off-by: Lorenzo Pieralisi <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/all/[email protected]
l1k pushed a commit that referenced this pull request Oct 4, 2025
The kernel forbids the creation of non-FDB nexthop groups with FDB
nexthops:

 # ip nexthop add id 1 via 192.0.2.1 fdb
 # ip nexthop add id 2 group 1
 Error: Non FDB nexthop group cannot have fdb nexthops.

And vice versa:

 # ip nexthop add id 3 via 192.0.2.2 dev dummy1
 # ip nexthop add id 4 group 3 fdb
 Error: FDB nexthop group can only have fdb nexthops.

However, as long as no routes are pointing to a non-FDB nexthop group,
the kernel allows changing the type of a nexthop from FDB to non-FDB and
vice versa:

 # ip nexthop add id 5 via 192.0.2.2 dev dummy1
 # ip nexthop add id 6 group 5
 # ip nexthop replace id 5 via 192.0.2.2 fdb
 # echo $?
 0

This configuration is invalid and can result in a NPD [1] since FDB
nexthops are not associated with a nexthop device:

 # ip route add 198.51.100.1/32 nhid 6
 # ping 198.51.100.1

Fix by preventing nexthop FDB status change while the nexthop is in a
group:

 # ip nexthop add id 7 via 192.0.2.2 dev dummy1
 # ip nexthop add id 8 group 7
 # ip nexthop replace id 7 via 192.0.2.2 fdb
 Error: Cannot change nexthop FDB status while in a group.

[1]
BUG: kernel NULL pointer dereference, address: 00000000000003c0
[...]
Oops: Oops: 0000 [#1] SMP
CPU: 6 UID: 0 PID: 367 Comm: ping Not tainted 6.17.0-rc6-virtme-gb65678cacc03 #1 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014
RIP: 0010:fib_lookup_good_nhc+0x1e/0x80
[...]
Call Trace:
 <TASK>
 fib_table_lookup+0x541/0x650
 ip_route_output_key_hash_rcu+0x2ea/0x970
 ip_route_output_key_hash+0x55/0x80
 __ip4_datagram_connect+0x250/0x330
 udp_connect+0x2b/0x60
 __sys_connect+0x9c/0xd0
 __x64_sys_connect+0x18/0x20
 do_syscall_64+0xa4/0x2a0
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

Fixes: 38428d6 ("nexthop: support for fdb ecmp nexthops")
Reported-by: [email protected]
Closes: https://lore.kernel.org/netdev/[email protected]/
Tested-by: [email protected]
Signed-off-by: Ido Schimmel <[email protected]>
Reviewed-by: David Ahern <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
Ido Schimmel says:

====================
nexthop: Various fixes

Patch #1 fixes a NPD that was recently reported by syzbot.

Patch #2 fixes an issue in the existing FIB nexthop selftest.

Patch #3 extends the selftest with test cases for the bug that was fixed
in the first patch.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
Add 0x29 as the accelerometer address for the Dell Latitude E6530 to
lis3lv02d_devices[].

The address was verified as below:

    $ cd /sys/bus/pci/drivers/i801_smbus/0000:00:1f.3
    $ ls -d i2c-*
    i2c-20
    $ sudo modprobe i2c-dev
    $ sudo i2cdetect 20
    WARNING! This program can confuse your I2C bus, cause data loss and worse!
    I will probe file /dev/i2c-20.
    I will probe address range 0x08-0x77.
    Continue? [Y/n] Y
         0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
    00:                         08 -- -- -- -- -- -- --
    10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    20: -- -- -- -- -- -- -- -- -- UU -- 2b -- -- -- --
    30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
    40: -- -- -- -- 44 -- -- -- -- -- -- -- -- -- -- --
    50: UU -- 52 -- -- -- -- -- -- -- -- -- -- -- -- --
    60: -- 61 -- -- -- -- -- -- -- -- -- -- -- -- -- --
    70: -- -- -- -- -- -- -- --
    $ cat /proc/cmdline
    BOOT_IMAGE=/vmlinuz-linux-cachyos-bore root=UUID=<redacted> rw loglevel=3 quiet dell_lis3lv02d.probe_i2c_addr=1
    $ sudo dmesg
    [    0.000000] Linux version 6.16.6-2-cachyos-bore (linux-cachyos-bore@cachyos) (gcc (GCC) 15.2.1 20250813, GNU ld (GNU Binutils) 2.45.0) #1 SMP PREEMPT_DYNAMIC Thu, 11 Sep 2025 16:01:12 +0000
    […]
    [    0.000000] DMI: Dell Inc. Latitude E6530/07Y85M, BIOS A22 11/30/2018
    […]
    [    5.166442] i2c i2c-20: Probing for lis3lv02d on address 0x29
    [    5.167854] i2c i2c-20: Detected lis3lv02d on address 0x29, please report this upstream to [email protected] so that a quirk can be added

Signed-off-by: Nickolay Goppen <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
Link: https://patch.msgid.link/20250917-dell-lis3lv02d-latitude-e6530-v1-1-8a6dec4e51e9@mainlining.org
Reviewed-by: Ilpo Järvinen <[email protected]>
Signed-off-by: Ilpo Järvinen <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
Running sha224_kunit on a KMSAN-enabled kernel results in a crash in
kmsan_internal_set_shadow_origin():

    BUG: unable to handle page fault for address: ffffbc3840291000
    #PF: supervisor read access in kernel mode
    #PF: error_code(0x0000) - not-present page
    PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0
    Oops: 0000 [#1] SMP NOPTI
    CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G                 N  6.17.0-rc3 torvalds#10 PREEMPT(voluntary)
    Tainted: [N]=TEST
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
    RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100
    [...]
    Call Trace:
    <TASK>
    __msan_memset+0xee/0x1a0
    sha224_final+0x9e/0x350
    test_hash_buffer_overruns+0x46f/0x5f0
    ? kmsan_get_shadow_origin_ptr+0x46/0xa0
    ? __pfx_test_hash_buffer_overruns+0x10/0x10
    kunit_try_run_case+0x198/0xa00

This occurs when memset() is called on a buffer that is not 4-byte aligned
and extends to the end of a guard page, i.e.  the next page is unmapped.

The bug is that the loop at the end of kmsan_internal_set_shadow_origin()
accesses the wrong shadow memory bytes when the address is not 4-byte
aligned.  Since each 4 bytes are associated with an origin, it rounds the
address and size so that it can access all the origins that contain the
buffer.  However, when it checks the corresponding shadow bytes for a
particular origin, it incorrectly uses the original unrounded shadow
address.  This results in reads from shadow memory beyond the end of the
buffer's shadow memory, which crashes when that memory is not mapped.

To fix this, correctly align the shadow address before accessing the 4
shadow bytes corresponding to each origin.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 2ef3cec ("kmsan: do not wipe out origin when doing partial unpoisoning")
Signed-off-by: Eric Biggers <[email protected]>
Tested-by: Alexander Potapenko <[email protected]>
Reviewed-by: Alexander Potapenko <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
l1k pushed a commit that referenced this pull request Oct 4, 2025
When the PAGEMAP_SCAN ioctl is invoked with vec_len = 0 reaches
pagemap_scan_backout_range(), kernel panics with null-ptr-deref:

[   44.936808] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[   44.937797] KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
[   44.938391] CPU: 1 UID: 0 PID: 2480 Comm: reproducer Not tainted 6.17.0-rc6 torvalds#22 PREEMPT(none)
[   44.939062] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[   44.939935] RIP: 0010:pagemap_scan_thp_entry.isra.0+0x741/0xa80

<snip registers, unreliable trace>

[   44.946828] Call Trace:
[   44.947030]  <TASK>
[   44.949219]  pagemap_scan_pmd_entry+0xec/0xfa0
[   44.952593]  walk_pmd_range.isra.0+0x302/0x910
[   44.954069]  walk_pud_range.isra.0+0x419/0x790
[   44.954427]  walk_p4d_range+0x41e/0x620
[   44.954743]  walk_pgd_range+0x31e/0x630
[   44.955057]  __walk_page_range+0x160/0x670
[   44.956883]  walk_page_range_mm+0x408/0x980
[   44.958677]  walk_page_range+0x66/0x90
[   44.958984]  do_pagemap_scan+0x28d/0x9c0
[   44.961833]  do_pagemap_cmd+0x59/0x80
[   44.962484]  __x64_sys_ioctl+0x18d/0x210
[   44.962804]  do_syscall_64+0x5b/0x290
[   44.963111]  entry_SYSCALL_64_after_hwframe+0x76/0x7e

vec_len = 0 in pagemap_scan_init_bounce_buffer() means no buffers are
allocated and p->vec_buf remains set to NULL.

This breaks an assumption made later in pagemap_scan_backout_range(), that
page_region is always allocated for p->vec_buf_index.

Fix it by explicitly checking p->vec_buf for NULL before dereferencing.

Other sites that might run into same deref-issue are already (directly or
transitively) protected by checking p->vec_buf.

Note:
From PAGEMAP_SCAN man page, it seems vec_len = 0 is valid when no output
is requested and it's only the side effects caller is interested in,
hence it passes check in pagemap_scan_get_args().

This issue was found by syzkaller.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 52526ca ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Signed-off-by: Jakub Acs <[email protected]>
Reviewed-by: Muhammad Usama Anjum <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Jinjiang Tu <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Penglei Jiang <[email protected]>
Cc: Mark Brown <[email protected]>
Cc: Baolin Wang <[email protected]>
Cc: Ryan Roberts <[email protected]>
Cc: Andrei Vagin <[email protected]>
Cc: "Michał Mirosław" <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
l1k pushed a commit that referenced this pull request Oct 9, 2025
pm_runtime_get_sync() and pm_runtime_put_autosuspend() were previously
called in cmdq_mbox_send_data(), which is under a spinlock in msg_submit()
(mailbox.c). This caused lockdep warnings such as "sleeping function
called from invalid context" when running with lockdebug enabled.

The BUG report:
  BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1164
  in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 3616, name: kworker/u17:3
    preempt_count: 1, expected: 0
    RCU nest depth: 0, expected: 0
    INFO: lockdep is turned off.
    irq event stamp: 0
    CPU: 1 PID: 3616 Comm: kworker/u17:3 Not tainted 6.1.87-lockdep-14133-g26e933aca785 #1
    Hardware name: Google Ciri sku0/unprovisioned board (DT)
    Workqueue: imgsys_runner imgsys_runner_func
    Call trace:
     dump_backtrace+0x100/0x120
     show_stack+0x20/0x2c
     dump_stack_lvl+0x84/0xb4
     dump_stack+0x18/0x48
     __might_resched+0x354/0x4c0
     __might_sleep+0x98/0xe4
     __pm_runtime_resume+0x70/0x124
     cmdq_mbox_send_data+0xe4/0xb1c
     msg_submit+0x194/0x2dc
     mbox_send_message+0x190/0x330
     imgsys_cmdq_sendtask+0x1618/0x2224
     imgsys_runner_func+0xac/0x11c
     process_one_work+0x638/0xf84
     worker_thread+0x808/0xcd0
     kthread+0x24c/0x324
     ret_from_fork+0x10/0x20

Additionally, pm_runtime_put_autosuspend() should be invoked from the
GCE IRQ handler to ensure the hardware has actually completed its work.

To resolve these issues, remove the pm_runtime calls from
cmdq_mbox_send_data() and delegate power management responsibilities
to the client driver.

Fixes: 8afe816 ("mailbox: mtk-cmdq-mailbox: Implement Runtime PM with autosuspend")
Signed-off-by: Jason-JH Lin <[email protected]>
Signed-off-by: Jassi Brar <[email protected]>
l1k pushed a commit that referenced this pull request Oct 9, 2025
The refactoring in 4292a1e ("PCI: Refactor distributing available
memory to use loops") switched pci_bus_distribute_available_resources() to
operate on an array of bridge windows. That accidentally looked up bus
resources via pci_bus_resource_n() and then passed those pointers to helper
routines that expect the resource to belong to the device. As soon as we
execute that code, pci_resource_num() warned because the resource wasn't in
the bridge's resource array.

This happens on my AMD Strix Halo machine with Thunderbolt device; the
error message is shown below:

  WARNING: CPU: 6 PID: 272 at drivers/pci/pci.h:471 pci_bus_distribute_available_resources+0x6ad/0x6d0
  CPU: 6 UID: 0 PID: 272 Comm: irq/33-pciehp Not tainted 6.17.0+ #1 PREEMPT(voluntary)
  Hardware name: PELADN YO Series/YO1, BIOS 1.04 05/15/2025
  RIP: 0010:pci_bus_distribute_available_resources+0x6ad/0x6d0
  Call Trace:
   pci_bus_distribute_available_resources+0x590/0x6d0
   pci_bridge_distribute_available_resources+0x62/0xb0
   pci_assign_unassigned_bridge_resources+0x65/0x1b0
   pciehp_configure_device+0x92/0x160
   pciehp_handle_presence_or_link_change+0x1b5/0x350
   pciehp_ist+0x147/0x1c0

Fix the regression by always fetching the resource directly from the bridge
with pci_resource_n(bridge, PCI_BRIDGE_RESOURCES + i). This restores the
original behaviour while keeping the refactored structure.  Then we can
successfully assign resources to the Thunderbolt device.

Fixes: 4292a1e ("PCI: Refactor distributing available memory to use loops")
Reported-by: Kenneth R. Crudup <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]
Signed-off-by: Yangyu Chen <[email protected]>
[bhelgaas: trim timestamps, etc from commit log]
Signed-off-by: Bjorn Helgaas <[email protected]>
Tested-By: Kenneth R. Crudup <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Link: https://patch.msgid.link/[email protected]
l1k pushed a commit that referenced this pull request Oct 9, 2025
I started seeing this in recent Fedora 42 kernels:

  # uname -a
  Linux number 6.16.3-200.fc42.x86_64 #1 SMP PREEMPT_DYNAMIC Sat Aug 23 17:02:17 UTC 2025 x86_64 GNU/Linux
  #
  # perf test vmlinux
    1: vmlinux symtab matches kallsyms                  : FAILED!
  #

Rust is enabled and these were the symbols causing the above failure,
i.e. found in vmlinux but not in /proc/kallsyms:

  $ grep -w N /proc/kallsyms
  0000000000000000 N __pfx__RNCINvNtNtNtCsbDUBuN8AbD4_4core4iter8adapters3map12map_try_foldjNtCs6vVzKs5jPr6_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
  0000000000000000 N _RNCINvNtNtNtCsbDUBuN8AbD4_4core4iter8adapters3map12map_try_foldjNtCs6vVzKs5jPr6_12drm_panic_qr7VersionuINtNtNtBa_3ops12control_flow11ControlFlowB10_ENcB10_0NCINvNvNtNtNtB8_6traits8iterator8Iterator4find5checkB10_NCNvMB12_B10_13from_segments0E0E0B12_
  $

So accept those 'N' symbols as well.

About them, from 'man nm':

           "N" The symbol is a debugging symbol.

           "n" The symbol is in a non-data, non-code, non-debug read-only section.

Reviewed-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Namhyung Kim <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
l1k pushed a commit that referenced this pull request Oct 9, 2025
The test starts a workload and then opens events. If the events fail
to open, for example because of perf_event_paranoid, the gopipe of the
workload is leaked and the file descriptor leak check fails when the
test exits. To avoid this cancel the workload when opening the events
fails.

Before:
```
$ perf test -vv 7
  7: PERF_RECORD_* events & perf_sample fields:
 --- start ---
test child forked, pid 1189568
Using CPUID GenuineIntel-6-B7-1
 ------------------------------------------------------------
perf_event_attr:
  type                    	   0 (PERF_TYPE_HARDWARE)
  config                  	   0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                	   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
 ------------------------------------------------------------
perf_event_attr:
  type                             0 (PERF_TYPE_HARDWARE)
  config                           0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/)
  disabled                         1
  exclude_kernel                   1
 ------------------------------------------------------------
sys_perf_event_open: pid 0  cpu -1  group_fd -1  flags 0x8 = 3
Attempt to add: software/cpu-clock/
..after resolving event: software/config=0/
cpu-clock -> software/cpu-clock/
 ------------------------------------------------------------
perf_event_attr:
  type                             1 (PERF_TYPE_SOFTWARE)
  size                             136
  config                           0x9 (PERF_COUNT_SW_DUMMY)
  sample_type                      IP|TID|TIME|CPU
  read_format                      ID|LOST
  disabled                         1
  inherit                          1
  mmap                             1
  comm                             1
  enable_on_exec                   1
  task                             1
  sample_id_all                    1
  mmap2                            1
  comm_exec                        1
  ksymbol                          1
  bpf_event                        1
  { wakeup_events, wakeup_watermark } 1
 ------------------------------------------------------------
sys_perf_event_open: pid 1189569  cpu 0  group_fd -1  flags 0x8
sys_perf_event_open failed, error -13
perf_evlist__open: Permission denied
 ---- end(-2) ----
Leak of file descriptor 6 that opened: 'pipe:[14200347]'
 ---- unexpected signal (6) ----
iFailed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
Failed to read build ID for //anon
    #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311
    #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0
    #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44
    #3 0x7f29ce849cc2 in raise raise.c:27
    #4 0x7f29ce8324ac in abort abort.c:81
    #5 0x565358f662d4 in check_leaks builtin-test.c:226
    #6 0x565358f6682e in run_test_child builtin-test.c:344
    torvalds#7 0x565358ef7121 in start_command run-command.c:128
    torvalds#8 0x565358f67273 in start_test builtin-test.c:545
    torvalds#9 0x565358f6771d in __cmd_test builtin-test.c:647
    torvalds#10 0x565358f682bd in cmd_test builtin-test.c:849
    torvalds#11 0x565358ee5ded in run_builtin perf.c:349
    torvalds#12 0x565358ee6085 in handle_internal_command perf.c:401
    torvalds#13 0x565358ee61de in run_argv perf.c:448
    torvalds#14 0x565358ee6527 in main perf.c:555
    torvalds#15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74
    torvalds#16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128
    torvalds#17 0x565358e391c1 in _start perf[851c1]
  7: PERF_RECORD_* events & perf_sample fields                       : FAILED!
```

After:
```
$ perf test 7
  7: PERF_RECORD_* events & perf_sample fields                       : Skip (permissions)
```

Fixes: 16d00fe ("perf tests: Move test__PERF_RECORD into separate object")
Signed-off-by: Ian Rogers <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Chun-Tse Shao <[email protected]>
Cc: Howard Chu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
l1k pushed a commit that referenced this pull request Oct 9, 2025
clang-18.1.3 on Ubuntu 24.04.2 reports warning:

  thread_loop.c:41:23: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
     41 |                 : /* in */ [i] "r" (i), [len] "r" (len)
        |                                     ^
  thread_loop.c:37:8: note: use constraint modifier "w"
     37 |                 "add %[i], %[i], #1\n"
        |                      ^~~~
        |                      %w[i]
  thread_loop.c:41:23: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
     41 |                 : /* in */ [i] "r" (i), [len] "r" (len)
        |                                     ^
  thread_loop.c:37:14: note: use constraint modifier "w"
     37 |                 "add %[i], %[i], #1\n"
        |                            ^~~~
        |                            %w[i]
  thread_loop.c:41:23: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
     41 |                 : /* in */ [i] "r" (i), [len] "r" (len)
        |                                     ^
  thread_loop.c:38:8: note: use constraint modifier "w"
     38 |                 "cmp %[i], %[len]\n"
        |                      ^~~~
        |                      %w[i]
  thread_loop.c:41:38: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
     41 |                 : /* in */ [i] "r" (i), [len] "r" (len)
        |                                                    ^
  thread_loop.c:38:14: note: use constraint modifier "w"
     38 |                 "cmp %[i], %[len]\n"
        |                            ^~~~~~
        |                            %w[len]

Use the modifier "w" for 32-bit register access.

Signed-off-by: Leo Yan <[email protected]>
Reviewed-by: Ian Rogers <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Cc: Palmer Dabbelt <[email protected]>
Cc: Albert Ou <[email protected]>
Cc: Alexandre Ghiti <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Justin Stitt <[email protected]>
Cc: Bill Wendling <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: James Clark <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Paul Walmsley <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
twilfredo pushed a commit to twilfredo/spdm-linux that referenced this pull request Oct 14, 2025
net/bridge/br_private.h:1627 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
7 locks held by socat/410:
 #0: ffff88800d7a9c90 (sk_lock-AF_INET){+.+.}-{0:0}, at: inet_stream_connect+0x43/0xa0
 l1k#1: ffffffff9a779900 (rcu_read_lock){....}-{1:3}, at: __ip_queue_xmit+0x62/0x1830
 [..]
 l1k#6: ffffffff9a779900 (rcu_read_lock){....}-{1:3}, at: nf_hook.constprop.0+0x8a/0x440

Call Trace:
 lockdep_rcu_suspicious.cold+0x4f/0xb1
 br_vlan_fill_forward_path_pvid+0x32c/0x410 [bridge]
 br_fill_forward_path+0x7a/0x4d0 [bridge]

Use to correct helper, non _rcu variant requires RTNL mutex.

Fixes: bcf2766 ("net: bridge: resolve forwarding path for VLAN tag actions in bridge devices")
Signed-off-by: Eric Woudstra <[email protected]>
Signed-off-by: Florian Westphal <[email protected]>
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4 participants