From: Roman Smirnov r.smirnov@omp.ru

stable inclusion from stable-v5.10.215 commit b0cb5564c3e8e0ee0a2d28c86fa7f02e82d64c3c category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9QGM9 CVE: CVE-2024-35925

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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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 Signed-off-by: Li Nan linan122@huawei.com --- block/blk-stat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-stat.c b/block/blk-stat.c index ae3dd1fb8e61..6e602f9b966e 100644 --- a/block/blk-stat.c +++ b/block/blk-stat.c @@ -28,7 +28,7 @@ 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);