[PATCH AUTOSEL 4.19 090/237] scsi: hisi_sas: Fix NULL pointer dereference

Sasha Levin
2019-11-16T15:43:05Z

From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>

[ Upstream commit f4445bb93d82a984657b469e63118c2794a4c3d3 ]

There is a NULL pointer dereference in case *slot* happens to be NULL at
lines 1053 and 1878:

struct hisi_sas_cq *cq =
&hisi_hba->cq[slot->dlvry_queue];

Notice that *slot* is being NULL checked at lines 1057 and 1881:
if (slot), which implies it may be NULL.

Fix this by placing the declaration and definition of variable cq, which
contains the pointer dereference slot->dlvry_queue, after slot has been
properly NULL checked.

Addresses-Coverity-ID: 1474515 ("Dereference before null check")
Addresses-Coverity-ID: 1474520 ("Dereference before null check")
Fixes: 584f53fe5f52 ("scsi: hisi_sas: Fix the race between IO completion and timeout for SMP/internal IO")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/hisi_sas/hisi_sas_main.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c
index d4a2625a44232..f478d1f50dfc0 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -1025,11 +1025,11 @@ static int hisi_sas_exec_internal_tmf_task(struct domain_device *device,
if ((task->task_state_flags & SAS_TASK_STATE_ABORTED)) {
if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) {
struct hisi_sas_slot *slot = task->lldd_task;
- struct hisi_sas_cq *cq =
- &hisi_hba->cq[slot->dlvry_queue];

dev_err(dev, "abort tmf: TMF task timeout and not done\n");
if (slot) {
+ struct hisi_sas_cq *cq =
+ &hisi_hba->cq[slot->dlvry_queue];
/*
* flush tasklet to avoid free'ing task
* before using task in IO completion
@@ -1856,10 +1856,10 @@ hisi_sas_internal_task_abort(struct hisi_hba *hisi_hba,
if ((task->task_state_flags & SAS_TASK_STATE_ABORTED)) {
if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) {
struct hisi_sas_slot *slot = task->lldd_task;
- struct hisi_sas_cq *cq =
- &hisi_hba->cq[slot->dlvry_queue];

if (slot) {
+ struct hisi_sas_cq *cq =
+ &hisi_hba->cq[slot->dlvry_queue];
/*
* flush tasklet to avoid free'ing task
* before using task in IO completion
--
2.20.1