6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Peter Wang peter.wang@mediatek.com
[ Upstream commit 74736103fb4123c71bf11fb7a6abe7c884c5269e ]
When ufshcd_abort_one is racing with the completion ISR, the completed tag of the request's mq_hctx pointer will be set to NULL by ISR. Return success when request is completed by ISR because ufshcd_abort_one does not need to do anything.
The racing flow is:
Thread A ufshcd_err_handler step 1 ... ufshcd_abort_one ufshcd_try_to_abort_task ufshcd_cmd_inflight(true) step 3 ufshcd_mcq_req_to_hwq blk_mq_unique_tag rq->mq_hctx->queue_num step 5
Thread B ufs_mtk_mcq_intr(cq complete ISR) step 2 scsi_done ... __blk_mq_free_request rq->mq_hctx = NULL; step 4
Below is KE back trace. ufshcd_try_to_abort_task: cmd at tag 41 not pending in the device. ufshcd_try_to_abort_task: cmd at tag=41 is cleared. Aborting tag 41 / CDB 0x28 succeeded Unable to handle kernel NULL pointer dereference at virtual address 0000000000000194 pc : [0xffffffddd7a79bf8] blk_mq_unique_tag+0x8/0x14 lr : [0xffffffddd6155b84] ufshcd_mcq_req_to_hwq+0x1c/0x40 [ufs_mediatek_mod_ise] do_mem_abort+0x58/0x118 el1_abort+0x3c/0x5c el1h_64_sync_handler+0x54/0x90 el1h_64_sync+0x68/0x6c blk_mq_unique_tag+0x8/0x14 ufshcd_err_handler+0xae4/0xfa8 [ufs_mediatek_mod_ise] process_one_work+0x208/0x4fc worker_thread+0x228/0x438 kthread+0x104/0x1d4 ret_from_fork+0x10/0x20
Fixes: 93e6c0e19d5b ("scsi: ufs: core: Clear cmd if abort succeeds in MCQ mode") Suggested-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Peter Wang peter.wang@mediatek.com Link: https://lore.kernel.org/r/20240628070030.30929-3-peter.wang@mediatek.com Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/ufs/core/ufshcd.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index f7d04f7c0017d..ad192b74536a2 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -6506,6 +6506,8 @@ static bool ufshcd_abort_one(struct request *rq, void *priv) /* Release cmd in MCQ mode if abort succeeds */ if (is_mcq_enabled(hba) && (*ret == 0)) { hwq = ufshcd_mcq_req_to_hwq(hba, scsi_cmd_to_rq(lrbp->cmd)); + if (!hwq) + return 0; spin_lock_irqsave(&hwq->cq_lock, flags); if (ufshcd_cmd_inflight(lrbp->cmd)) ufshcd_release_scsi_cmd(hba, lrbp);