4.19-stable review patch. If anyone has any objections, please let me know.
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From: Roman Smirnov r.smirnov@omp.ru
[ Upstream commit 93f52fbeaf4b676b21acfe42a5152620e6770d02 ]
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: Sasha Levin sashal@kernel.org --- 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 7587b1c3caaf5..507ac714423bd 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);