[PATCH v1] scsi: ufs: fix tm cmd timeout/ISR racing issue

[<peter.wang@mediatek.com>]

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

When tmc 100 ms timeout and recevied tmc complete ISR concurrently,
Bug happen because complete NULL poiner and KE.
Fix this racing issue by check NULL and use host_lock protect.

Signed-off-by: Peter Wang <peter.wang@mediatek.com>
---
 drivers/scsi/ufs/ufshcd.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 5c6a58a666d2..6821ceb6783e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6442,7 +6442,8 @@ static irqreturn_t ufshcd_tmc_handler(struct ufs_hba *hba)
 		struct request *req = hba->tmf_rqs[tag];
 		struct completion *c = req->end_io_data;
 
-		complete(c);
+		if (c)
+			complete(c);
 		ret = IRQ_HANDLED;
 	}
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
@@ -6597,7 +6598,10 @@ static int __ufshcd_issue_tm_cmd(struct ufs_hba *hba,
 		 * Make sure that ufshcd_compl_tm() does not trigger a
 		 * use-after-free.
 		 */
+		spin_lock_irqsave(hba->host->host_lock, flags);
 		req->end_io_data = NULL;
+		spin_unlock_irqrestore(hba->host->host_lock, flags);
+
 		ufshcd_add_tm_upiu_trace(hba, task_tag, UFS_TM_ERR);
 		dev_err(hba->dev, "%s: task management cmd 0x%.2x timed-out\n",
 				__func__, tm_function);
-- 
2.18.0