2018-10-18 17:52:06

by Gustavo A. R. Silva

[permalink] [raw]
Subject: [PATCH v2] scsi: hisi_sas: Fix NULL pointer dereference

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 <[email protected]>
---
Changes in v2:
- Fix another instance of the same issue at line 1053.
- Update commit log.

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 2e5eaf1..b3f01d5 100644
--- a/drivers/scsi/hisi_sas/hisi_sas_main.c
+++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
@@ -1050,11 +1050,11 @@ 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
@@ -1875,10 +1875,10 @@ 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
--
2.7.4



2018-10-19 00:54:53

by chenxiang (M)

[permalink] [raw]
Subject: Re: [PATCH v2] scsi: hisi_sas: Fix NULL pointer dereference

在 2018/10/19 0:59, Gustavo A. R. Silva 写道:
> 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 <[email protected]>

Reviewed-by: Xiang Chen <[email protected]>
Thanks!

> ---
> Changes in v2:
> - Fix another instance of the same issue at line 1053.
> - Update commit log.
>
> 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 2e5eaf1..b3f01d5 100644
> --- a/drivers/scsi/hisi_sas/hisi_sas_main.c
> +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c
> @@ -1050,11 +1050,11 @@ 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
> @@ -1875,10 +1875,10 @@ 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



2018-10-19 22:29:49

by Martin K. Petersen

[permalink] [raw]
Subject: Re: [PATCH v2] scsi: hisi_sas: Fix NULL pointer dereference


Gustavo,

> 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.

Applied to 4.20/scsi-queue, thanks!

--
Martin K. Petersen Oracle Linux Engineering

2018-10-20 06:37:18

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH v2] scsi: hisi_sas: Fix NULL pointer dereference



On 10/20/18 12:28 AM, Martin K. Petersen wrote:
>
> Gustavo,
>
>> 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.
>
> Applied to 4.20/scsi-queue, thanks!
>

Glad to help. :)

Thanks
--
Gustavo