[PATCH v2] ufs: core: fix racing issue between ufshcd_mcq_abort and ISR

[<peter.wang@mediatek.com>]

From: Peter Wang <peter.wang@mediatek.com>

If command timeout happen and cq complete irq raise at the same time,
ufshcd_mcq_abort null the lprb->cmd and NULL poiner KE in ISR.
Below is error log.

ufshcd_abort: Device abort task at tag 18
Unable to handle kernel NULL pointer dereference at virtual address
0000000000000108
pc : [0xffffffe27ef867ac] scsi_dma_unmap+0xc/0x44
lr : [0xffffffe27f1b898c] ufshcd_release_scsi_cmd+0x24/0x114

Fixes: f1304d442077 ("scsi: ufs: mcq: Added ufshcd_mcq_abort()")
Cc: stable@vger.kernel.org
Signed-off-by: Peter Wang <peter.wang@mediatek.com>
---
 drivers/ufs/core/ufs-mcq.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/ufs/core/ufs-mcq.c b/drivers/ufs/core/ufs-mcq.c
index 2ba8ec254dce..6ea96406f2bf 100644
--- a/drivers/ufs/core/ufs-mcq.c
+++ b/drivers/ufs/core/ufs-mcq.c
@@ -630,6 +630,7 @@ int ufshcd_mcq_abort(struct scsi_cmnd *cmd)
 	int tag = scsi_cmd_to_rq(cmd)->tag;
 	struct ufshcd_lrb *lrbp = &hba->lrb[tag];
 	struct ufs_hw_queue *hwq;
+	unsigned long flags;
 	int err = FAILED;
 
 	if (!ufshcd_cmd_inflight(lrbp->cmd)) {
@@ -670,8 +671,10 @@ int ufshcd_mcq_abort(struct scsi_cmnd *cmd)
 	}
 
 	err = SUCCESS;
+	spin_lock_irqsave(&hwq->cq_lock, flags);
 	if (ufshcd_cmd_inflight(lrbp->cmd))
 		ufshcd_release_scsi_cmd(hba, lrbp);
+	spin_unlock_irqrestore(&hwq->cq_lock, flags);
 
 out:
 	return err;
-- 
2.18.0