* [PATCH] dm cache: fix divide error in too_many_discard_blocks()
@ 2026-11-06 18:10 Drif Abdelmalek Mohamed Said
2026-11-06 18:10 ` syzbot
2026-11-06 18:10 ` syzbot
0 siblings, 2 replies; 3+ messages in thread
From: Drif Abdelmalek Mohamed Said @ 2026-11-06 18:10 UTC (permalink / raw)
To: syzbot+3e16980543e238b95bd1
Cc: syzbot+7ff3adde89dd795ad4c4, kmsan-dev, glider, dvyukov, jack,
linux-fsdevel, linux-kernel, Drif Abdelmalek Mohamed Said
#syz test
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 1a5072425c4a..2d40d6047ef1 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2383,9 +2383,7 @@ static int create_cache_policy(struct cache *cache, struct cache_args *ca,
static bool too_many_discard_blocks(sector_t discard_block_size,
sector_t origin_size)
{
- (void) sector_div(origin_size, discard_block_size);
-
- return origin_size > MAX_DISCARD_BLOCKS;
+ return div64_u64(origin_size, discard_block_size) > MAX_DISCARD_BLOCKS;
}
static sector_t calculate_discard_block_size(sector_t cache_block_size,
--
2.43.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] dm cache: fix divide error in too_many_discard_blocks()
2026-11-06 18:10 [PATCH] dm cache: fix divide error in too_many_discard_blocks() Drif Abdelmalek Mohamed Said
@ 2026-11-06 18:10 ` syzbot
2026-11-06 18:10 ` syzbot
1 sibling, 0 replies; 3+ messages in thread
From: syzbot @ 2026-11-06 18:10 UTC (permalink / raw)
To: drifabdelmalekmohamedsaid
Cc: drifabdelmalekmohamedsaid, dvyukov, glider, jack, kmsan-dev,
linux-fsdevel, linux-kernel, syzkaller-upstream-moderation
> #syz test
This crash does not have a reproducer. I cannot test it.
>
> diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
> index 1a5072425c4a..2d40d6047ef1 100644
> --- a/drivers/md/dm-cache-target.c
> +++ b/drivers/md/dm-cache-target.c
> @@ -2383,9 +2383,7 @@ static int create_cache_policy(struct cache *cache, struct cache_args *ca,
> static bool too_many_discard_blocks(sector_t discard_block_size,
> sector_t origin_size)
> {
> - (void) sector_div(origin_size, discard_block_size);
> -
> - return origin_size > MAX_DISCARD_BLOCKS;
> + return div64_u64(origin_size, discard_block_size) > MAX_DISCARD_BLOCKS;
> }
>
> static sector_t calculate_discard_block_size(sector_t cache_block_size,
> --
> 2.43.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] dm cache: fix divide error in too_many_discard_blocks()
2026-11-06 18:10 [PATCH] dm cache: fix divide error in too_many_discard_blocks() Drif Abdelmalek Mohamed Said
2026-11-06 18:10 ` syzbot
@ 2026-11-06 18:10 ` syzbot
1 sibling, 0 replies; 3+ messages in thread
From: syzbot @ 2026-11-06 18:10 UTC (permalink / raw)
To: drifabdelmalekmohamedsaid
Cc: drifabdelmalekmohamedsaid, dvyukov, glider, jack, kmsan-dev,
linux-fsdevel, linux-kernel, syzkaller-upstream-moderation
> #syz test
This crash does not have a reproducer. I cannot test it.
>
> diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
> index 1a5072425c4a..2d40d6047ef1 100644
> --- a/drivers/md/dm-cache-target.c
> +++ b/drivers/md/dm-cache-target.c
> @@ -2383,9 +2383,7 @@ static int create_cache_policy(struct cache *cache, struct cache_args *ca,
> static bool too_many_discard_blocks(sector_t discard_block_size,
> sector_t origin_size)
> {
> - (void) sector_div(origin_size, discard_block_size);
> -
> - return origin_size > MAX_DISCARD_BLOCKS;
> + return div64_u64(origin_size, discard_block_size) > MAX_DISCARD_BLOCKS;
> }
>
> static sector_t calculate_discard_block_size(sector_t cache_block_size,
> --
> 2.43.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2026-11-06 18:10 [PATCH] dm cache: fix divide error in too_many_discard_blocks() Drif Abdelmalek Mohamed Said
2026-11-06 18:10 ` syzbot
2026-11-06 18:10 ` syzbot
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