From: Matthew Wilcox <willy@infradead.org>
To: Jeongjun Park <aha310510@gmail.com>
Cc: akpm@linux-foundation.org, kasong@tencent.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
syzbot+fa43f1b63e3aa6f66329@syzkaller.appspotmail.com
Subject: Re: [PATCH] mm: swap: prevent possible data-race in __try_to_reclaim_swap
Date: Fri, 4 Oct 2024 15:34:21 +0100 [thread overview]
Message-ID: <Zv_87TBZnh2lIwyH@casper.infradead.org> (raw)
In-Reply-To: <20241004142504.4379-1-aha310510@gmail.com>
On Fri, Oct 04, 2024 at 11:25:04PM +0900, Jeongjun Park wrote:
> A report [1] was uploaded from syzbot.
>
> In the previous commit 862590ac3708 ("mm: swap: allow cache reclaim to skip
> slot cache"), the __try_to_reclaim_swap() function reads offset and nr_pages
> from folio without folio_lock protection.
Umm. You don't need folio_lock to read nr_pages. Holding a refcount
is sufficient to stabilise nr_pages. I cannot speak to folio->swap
though (and the KCSAN report does appear to be pointing to folio->swap).
next prev parent reply other threads:[~2024-10-04 14:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-04 14:25 Jeongjun Park
2024-10-04 14:34 ` Matthew Wilcox [this message]
2024-10-04 14:50 ` Jeongjun Park
2024-10-06 20:15 ` Kairui Song
2024-10-07 0:49 ` Jeongjun Park
2024-10-07 5:06 ` kernel test robot
2024-10-08 1:30 ` Andrew Morton
2024-10-08 2:35 ` Jeongjun Park
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