pds_core: remove write-after-free of client_id

[ Upstream commit dfd7601 ]

A use-after-free error popped up in stress testing:

[Mon Apr 21 21:21:33 2025] BUG: KFENCE: use-after-free write in pdsc_auxbus_dev_del+0xef/0x160 [pds_core]
[Mon Apr 21 21:21:33 2025] Use-after-free write at 0x000000007013ecd1 (in kfence-#47):
[Mon Apr 21 21:21:33 2025]  pdsc_auxbus_dev_del+0xef/0x160 [pds_core]
[Mon Apr 21 21:21:33 2025]  pdsc_remove+0xc0/0x1b0 [pds_core]
[Mon Apr 21 21:21:33 2025]  pci_device_remove+0x24/0x70
[Mon Apr 21 21:21:33 2025]  device_release_driver_internal+0x11f/0x180
[Mon Apr 21 21:21:33 2025]  driver_detach+0x45/0x80
[Mon Apr 21 21:21:33 2025]  bus_remove_driver+0x83/0xe0
[Mon Apr 21 21:21:33 2025]  pci_unregister_driver+0x1a/0x80

The actual device uninit usually happens on a separate thread
scheduled after this code runs, but there is no guarantee of order
of thread execution, so this could be a problem.  There's no
actual need to clear the client_id at this point, so simply
remove the offending code.

Fixes: 1065903 ("pds_core: add the aux client API")
Signed-off-by: Shannon Nelson <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: emusln

drivers/net/ethernet/amd/pds_core/auxbus.c

@@ -186,7 +186,6 @@ void pdsc_auxbus_dev_del(struct pdsc *cf, struct pdsc *pf,
 	pds_client_unregister(pf, padev->client_id);
 	auxiliary_device_delete(&padev->aux_dev);
 	auxiliary_device_uninit(&padev->aux_dev);
-	padev->client_id = 0;
 	*pd_ptr = NULL;
 
 	mutex_unlock(&pf->config_lock);