block: prevent division by zero in blk_rq_stat_sum()

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>
Link: https://lore.kernel.org/r/20240305134509.23108-1-r.smirnov@omp.ru
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Roman Smirnov 2024-03-05 16:45:09 +03:00 committed by Jens Axboe
parent e6dfe748f0
commit 93f52fbeaf
1 changed files with 1 additions and 1 deletions

View File

@ -27,7 +27,7 @@ void blk_rq_stat_init(struct blk_rq_stat *stat)
/* src is a per-cpu stat, mean isn't initialized */ /* 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) 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; return;
dst->min = min(dst->min, src->min); dst->min = min(dst->min, src->min);