* [PATCH] md: fix potential NULL pointer dereference in md_super_write
@ 2025-05-23 9:11 Ye Chey
0 siblings, 0 replies; 3+ messages in thread
From: Ye Chey @ 2025-05-23 9:11 UTC (permalink / raw)
To: song, yukuai3; +Cc: linux-raid, linux-kernel, Ye Chey
The bio_alloc_bioset() call in md_super_write() could fail under memory
pressure and return NULL. Add a check to handle this case gracefully by
returning early, preventing a potential NULL pointer dereference.
Signed-off-by: Ye Chey <yechey@ai-sast.com>
---
drivers/md/md.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9daa78c5f..492cbc1c7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1002,6 +1002,9 @@ void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
REQ_OP_WRITE | REQ_SYNC | REQ_IDLE | REQ_META
| REQ_PREFLUSH | REQ_FUA,
GFP_NOIO, &mddev->sync_set);
+ if (!bio) {
+ return;
+ }
atomic_inc(&rdev->nr_pending);
--
2.44.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH] md: fix potential NULL pointer dereference in md_super_write
@ 2025-05-23 9:35 Ye Chey
2025-05-23 9:59 ` Yu Kuai
0 siblings, 1 reply; 3+ messages in thread
From: Ye Chey @ 2025-05-23 9:35 UTC (permalink / raw)
To: song, yukuai3; +Cc: linux-raid, linux-kernel, Ye Chey
The bio_alloc_bioset() call in md_super_write() could fail under memory
pressure and return NULL. Add a check to handle this case gracefully by
returning early, preventing a potential NULL pointer dereference.
Signed-off-by: Ye Chey <yechey@ai-sast.com>
---
drivers/md/md.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9daa78c5f..a0e2d90d4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1002,6 +1002,8 @@ void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
REQ_OP_WRITE | REQ_SYNC | REQ_IDLE | REQ_META
| REQ_PREFLUSH | REQ_FUA,
GFP_NOIO, &mddev->sync_set);
+ if (!bio)
+ return;
atomic_inc(&rdev->nr_pending);
--
2.44.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] md: fix potential NULL pointer dereference in md_super_write
2025-05-23 9:35 [PATCH] md: fix potential NULL pointer dereference in md_super_write Ye Chey
@ 2025-05-23 9:59 ` Yu Kuai
0 siblings, 0 replies; 3+ messages in thread
From: Yu Kuai @ 2025-05-23 9:59 UTC (permalink / raw)
To: Ye Chey, song; +Cc: linux-raid, linux-kernel, yukuai (C)
Hi,
在 2025/05/23 17:35, Ye Chey 写道:
> The bio_alloc_bioset() call in md_super_write() could fail under memory
> pressure and return NULL. Add a check to handle this case gracefully by
> returning early, preventing a potential NULL pointer dereference.
NAK, if you read the comments of bio_alloc_bioset(), you'll know there
are cases bio_alloc_bioset() will never return NULL.
Thanks,
Kuai
>
> Signed-off-by: Ye Chey <yechey@ai-sast.com>
> ---
> drivers/md/md.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 9daa78c5f..a0e2d90d4 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -1002,6 +1002,8 @@ void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
> REQ_OP_WRITE | REQ_SYNC | REQ_IDLE | REQ_META
> | REQ_PREFLUSH | REQ_FUA,
> GFP_NOIO, &mddev->sync_set);
> + if (!bio)
> + return;
>
> atomic_inc(&rdev->nr_pending);
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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