6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Shannon Nelson shannon.nelson@amd.com
[ Upstream commit dfd76010f8e821b66116dec3c7d90dd2403d1396 ]
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: 10659034c622 ("pds_core: add the aux client API") Signed-off-by: Shannon Nelson shannon.nelson@amd.com Reviewed-by: Simon Horman horms@kernel.org Link: https://patch.msgid.link/20250425203857.71547-1-shannon.nelson@amd.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/amd/pds_core/auxbus.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/drivers/net/ethernet/amd/pds_core/auxbus.c b/drivers/net/ethernet/amd/pds_core/auxbus.c index 4d3387bebe6a4..889a18962270a 100644 --- a/drivers/net/ethernet/amd/pds_core/auxbus.c +++ b/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);