From: Johannes Weiner <hannes@cmpxchg.org>
To: Nhat Pham <nphamcs@gmail.com>
Cc: akpm@linux-foundation.org, kernel-team@meta.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, willy@infradead.org, david@redhat.com,
ryan.roberts@arm.com, ying.huang@intel.com,
viro@zeniv.linux.org.uk, kasong@tencent.com,
yosryahmed@google.com, shakeel.butt@linux.dev,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] cachestat: do not flush stats in recency check
Date: Thu, 27 Jun 2024 16:41:16 -0400 [thread overview]
Message-ID: <20240627204116.GD469122@cmpxchg.org> (raw)
In-Reply-To: <20240627201737.3506959-1-nphamcs@gmail.com>
On Thu, Jun 27, 2024 at 01:17:37PM -0700, Nhat Pham wrote:
> syzbot detects that cachestat() is flushing stats, which can sleep, in
> its RCU read section (see [1]). This is done in the
> workingset_test_recent() step (which checks if the folio's eviction is
> recent).
>
> Move the stat flushing step to before the RCU read section of cachestat,
> and skip stat flushing during the recency check.
>
> [1]: https://lore.kernel.org/cgroups/000000000000f71227061bdf97e0@google.com/
>
> Reported-by: syzbot+b7f13b2d0cc156edf61a@syzkaller.appspotmail.com
> Closes: https://lore.kernel.org/cgroups/000000000000f71227061bdf97e0@google.com/
> Debugged-by: Johannes Weiner <hannes@cmpxchg.org>
> Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Nhat Pham <nphamcs@gmail.com>
> Fixes: b00684722262 ("mm: workingset: move the stats flush into workingset_test_recent()")
> Cc: stable@vger.kernel.org # v6.8+
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
next prev parent reply other threads:[~2024-06-27 20:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <000000000000f71227061bdf97e0@google.com>
2024-06-27 20:17 ` [PATCH] cachestat: do not flush stats in recency check Nhat Pham
2024-06-27 20:41 ` Johannes Weiner [this message]
2024-06-28 1:58 ` Shakeel Butt
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