From: SeongJae Park <sj@kernel.org>
To: Honggyu Kim <honggyu.kim@sk.com>
Cc: SeongJae Park <sj@kernel.org>,
damon@lists.linux.dev, Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, kernel_team@skhynix.com,
stable@vger.kernel.org
Subject: Re: [PATCH v3 4/4] mm/damon: fix divide by zero in damon_get_intervals_score()
Date: Tue, 1 Jul 2025 17:19:02 -0700 [thread overview]
Message-ID: <20250702001902.937-1-sj@kernel.org> (raw)
In-Reply-To: <20250702000205.1921-5-honggyu.kim@sk.com>
Hello Honggyu,
On Wed, 2 Jul 2025 09:02:04 +0900 Honggyu Kim <honggyu.kim@sk.com> wrote:
> The current implementation allows having zero size regions with no
> special reasons, but damon_get_intervals_score() gets crashed by divide
> by zero when the region size is zero.
>
> [ 29.403950] Oops: divide error: 0000 [#1] SMP NOPTI
>
> This patch fixes the bug, but does not disallow zero size regions to
> keep the backward compatibility since disallowing zero size regions
> might be a breaking change for some users.
>
> In addition, the same crash can happen when intervals_goal.access_bp is
> zero so this should be fixed in stable trees as well.
Thank you for this fix!
>
> Fixes: f04b0fedbe71 ("mm/damon/core: implement intervals auto-tuning")
> Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
> Cc: stable@vger.kernel.org
Reviewed-by: SeongJae Park <sj@kernel.org>
Thanks,
SJ
[...]
prev parent reply other threads:[~2025-07-02 0:19 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-02 0:02 [PATCH v3 0/4] mm/damon: fix divide by zero and its samples Honggyu Kim
2025-07-02 0:02 ` [PATCH v3 1/4] samples/damon: fix damon sample prcl for start failure Honggyu Kim
2025-07-02 0:02 ` [PATCH v3 2/4] samples/damon: fix damon sample wsse " Honggyu Kim
2025-07-02 0:02 ` [PATCH v3 3/4] samples/damon: fix damon sample mtier " Honggyu Kim
2025-07-02 0:02 ` [PATCH v3 4/4] mm/damon: fix divide by zero in damon_get_intervals_score() Honggyu Kim
2025-07-02 0:19 ` SeongJae Park [this message]
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