This is a note to let you know that I've just added the patch titled scsi: libsas: Fix use-after-free bug in smp_execute_task_sg() to the 6.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: scsi-libsas-fix-use-after-free-bug-in-smp_execute_ta.patch and it can be found in the queue-6.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit f55d7807bfb9223f699cf25a496da4a2e174e1a2 Author: Duoming Zhou <duoming@xxxxxxxxxx> Date: Tue Sep 20 22:42:13 2022 +0800 scsi: libsas: Fix use-after-free bug in smp_execute_task_sg() [ Upstream commit 46ba53c30666717cb06c2b3c5d896301cd00d0c0 ] When executing SMP task failed, the smp_execute_task_sg() calls del_timer() to delete "slow_task->timer". However, if the timer handler sas_task_internal_timedout() is running, the del_timer() in smp_execute_task_sg() will not stop it and a UAF will happen. The process is shown below: (thread 1) | (thread 2) smp_execute_task_sg() | sas_task_internal_timedout() ... | del_timer() | ... | ... sas_free_task(task) | kfree(task->slow_task) //FREE| | task->slow_task->... //USE Fix by calling del_timer_sync() in smp_execute_task_sg(), which makes sure the timer handler have finished before the "task->slow_task" is deallocated. Link: https://lore.kernel.org/r/20220920144213.10536-1-duoming@xxxxxxxxxx Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver") Reviewed-by: Jason Yan <yanaijie@xxxxxxxxxx> Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c index fa2209080cc2..5ce251830104 100644 --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -67,7 +67,7 @@ static int smp_execute_task_sg(struct domain_device *dev, res = i->dft->lldd_execute_task(task, GFP_KERNEL); if (res) { - del_timer(&task->slow_task->timer); + del_timer_sync(&task->slow_task->timer); pr_notice("executing SMP task failed:%d\n", res); break; }