RPi3B+: Kernel underflow or use-after-free #5730
Description
Describe the bug
Frequently when running Kodi I'm getting this error in dmesg:
[ 1373.539694] ------------[ cut here ]------------
[ 1373.546813] WARNING: CPU: 1 PID: 423 at lib/refcount.c:87 refcount_dec_not_one+0xac/0xbc
[ 1373.557467] refcount_t: underflow; use-after-free.
[ 1373.564786] Modules linked in: rpcsec_gss_krb5 bcm2835_codec(C) bcm2835_v4l2(C) bcm2835_isp(C) bcm2835_mmal_vchiq(C) v4l2_mem2mem videobuf2_vmalloc videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 videobuf2_common raspberrypi_hwmon videodev vc_sm_cma(C) mc i2c_bcm2835 raspberrypi_gpiomem cfg80211 rfkill uio_pdrv_genirq uio sch_fq_codel snd_bcm2835(C) fuse dm_mod zstd zram zsmalloc ip_tables x_tables ipv6 vc4 snd_soc_hdmi_codec snd_soc_core snd_compress snd_pcm_dmaengine snd_pcm snd_timer snd drm_display_helper drm_dma_helper drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm drm_panel_orientation_quirks backlight cec
[ 1373.629538] CPU: 1 PID: 423 Comm: kodi.bin Tainted: G C 6.1.62-3-rpi-ARCH #1
[ 1373.640926] Hardware name: BCM2835
[ 1373.647324] unwind_backtrace from show_stack+0x18/0x1c
[ 1373.655492] show_stack from dump_stack_lvl+0x90/0xac
[ 1373.663452] dump_stack_lvl from __warn+0x80/0x11c
[ 1373.671112] __warn from warn_slowpath_fmt+0x12c/0x198
[ 1373.679178] warn_slowpath_fmt from refcount_dec_not_one+0xac/0xbc
[ 1373.688256] refcount_dec_not_one from vc4_bo_dec_usecnt+0x2c/0xd8 [vc4]
[ 1373.698090] vc4_bo_dec_usecnt [vc4] from drm_atomic_helper_cleanup_planes+0x64/0x78 [drm_kms_helper]
[ 1373.710486] drm_atomic_helper_cleanup_planes [drm_kms_helper] from vc4_atomic_commit_tail+0x158/0x904 [vc4]
[ 1373.723526] vc4_atomic_commit_tail [vc4] from commit_tail+0xa4/0x198 [drm_kms_helper]
[ 1373.734601] commit_tail [drm_kms_helper] from drm_atomic_helper_commit+0x13c/0x160 [drm_kms_helper]
[ 1373.746898] drm_atomic_helper_commit [drm_kms_helper] from drm_atomic_commit+0xb4/0xe8 [drm]
[ 1373.758855] drm_atomic_commit [drm] from drm_mode_atomic_ioctl+0x890/0xb1c [drm]
[ 1373.769826] drm_mode_atomic_ioctl [drm] from drm_ioctl+0x1d8/0x388 [drm]
[ 1373.780119] drm_ioctl [drm] from sys_ioctl+0x118/0xa98
[ 1373.788648] sys_ioctl from ret_fast_syscall+0x0/0x1c
[ 1373.796719] Exception stack(0xf12b1fa8 to 0xf12b1ff0)
[ 1373.804810] 1fa0: 059689e0 bebd0658 00000000 c03864bc bebd0658 00000000
[ 1373.816042] 1fc0: 059689e0 bebd0658 c03864bc 00000036 059efbb0 048005a0 048005f8 059efbdc
[ 1373.827268] 1fe0: b4e2ae58 bebd0600 b544627c b4d94f3c
[ 1373.835456] ---[ end trace 0000000000000000 ]---
Steps to reproduce the behaviour
I don't know what triggers the underflow other than running Kodi. But it also doesn't seem to affect Kodi. The issue started to appear after I updated Kodi to a version that contains xbmc/xbmc#23921 so EGL fences or drmModeAtomicCommit with the DRM_MODE_ATOMIC_NONBLOCK flag may be part of the issue.
Device (s)
Raspberry Pi 3 Mod. B+
System
OS: Arch Linux ARM
Kernel (PKGBUILD): Linux alarmpi 6.1.62-3-rpi-ARCH #1 SMP Mon Nov 20 13:09:55 MST 2023 armv7l GNU/Linux
vcgencmd version:
Oct 17 2023 15:42:39
Copyright (c) 2012 Broadcom
version 30f0c5e4d076da3ab4f341d88e7d505760b93ad7 (clean) (release) (start)
Logs
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Additional context
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