scsi: ufs: core: Fix racing issue between ufshcd_mcq_abort() and ISR

If command timeout happens and cq complete IRQ is raised at the same time,
ufshcd_mcq_abort clears lprb->cmd and a NULL pointer deref happens in the
ISR. 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: f1304d4 ("scsi: ufs: mcq: Added ufshcd_mcq_abort()")
Cc: [email protected]
Signed-off-by: Peter Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

Author: ptr324

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;