diff mbox series

block: prevent division by zero in blk_rq_stat_sum()

Message ID 20240305134509.23108-1-r.smirnov@omp.ru (mailing list archive)
State New, archived
Headers show
Series block: prevent division by zero in blk_rq_stat_sum() | expand

Commit Message

Roman Smirnov March 5, 2024, 1:45 p.m. UTC 
The expression dst->nr_samples + src->nr_samples may
have zero value on overflow. It is necessary to add
a check to avoid division by zero.

Found by Linux Verification Center (linuxtesting.org) with Svace.

Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
---
 block/blk-stat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jens Axboe March 6, 2024, 3:35 p.m. UTC | #1 
On Tue, 05 Mar 2024 16:45:09 +0300, Roman Smirnov wrote:
> The expression dst->nr_samples + src->nr_samples may
> have zero value on overflow. It is necessary to add
> a check to avoid division by zero.
> 
> Found by Linux Verification Center (linuxtesting.org) with Svace.
> 
> 
> [...]

Applied, thanks!

[1/1] block: prevent division by zero in blk_rq_stat_sum()
      commit: 93f52fbeaf4b676b21acfe42a5152620e6770d02

Best regards,
diff mbox series

Patch

diff --git a/block/blk-stat.c b/block/blk-stat.c
index 7ff76ae6c76a..e42c263e53fb 100644
--- a/block/blk-stat.c
+++ b/block/blk-stat.c
@@ -27,7 +27,7 @@  void blk_rq_stat_init(struct blk_rq_stat *stat)
 /* src is a per-cpu stat, mean isn't initialized */
 void blk_rq_stat_sum(struct blk_rq_stat *dst, struct blk_rq_stat *src)
 {
-	if (!src->nr_samples)
+	if (dst->nr_samples + src->nr_samples <= dst->nr_samples)
 		return;
 
 	dst->min = min(dst->min, src->min);