From: Chuck Lever III <chuck.lever@oracle.com>
To: David Wysochanski <dwysocha@redhat.com>,
Dave Wysochanski <wysochanski@pobox.com>
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>
Subject: Re: BUG in nfs_read_folio() when tracing is enabled
Date: Fri, 5 Jul 2024 13:45:11 +0000 [thread overview]
Message-ID: <FF24B77F-638E-4F31-ABB6-B07D48AF73B4@oracle.com> (raw)
In-Reply-To: <ZoTc3-Bzfr-gY4-o@infradead.org>
> On Jul 3, 2024, at 1:08 AM, Christoph Hellwig <hch@infradead.org> wrote:
>
> On Tue, Jul 02, 2024 at 05:33:58PM -0400, David Wysochanski wrote:
>
> [annoying full quote snipped]
>
>> Was your test running both reads and truncates on the same file in parallel?
>>
>> Once the read completes I believe the page is unlocked. Then if
>> truncates are running in parallel, then I think this can happen
>> (folio->mapping = NULL as a result of truncate).
>
> Yes, folio->mapping is only stable when the folio is locked.
So Dave, I haven't tested the patch you posted a couple
days ago, because there hasn't been a clear answer about
whether nfs_read_folio() needs to protect itself against
the ->mapping changing, in which case, that's probably
a better fix.
--
Chuck Lever
next prev parent reply other threads:[~2024-07-05 13:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-19 20:45 BUG in nfs_read_folio() when tracing is enabled Chuck Lever III
2024-07-02 20:59 ` David Wysochanski
2024-07-02 21:14 ` David Wysochanski
2024-07-02 21:17 ` Chuck Lever III
2024-07-02 21:33 ` David Wysochanski
2024-07-03 5:08 ` Christoph Hellwig
2024-07-05 13:45 ` Chuck Lever III [this message]
2024-07-05 13:47 ` Christoph Hellwig
2024-07-09 15:45 ` David Wysochanski
2024-07-10 6:33 ` Christoph Hellwig
2024-07-03 13:40 ` Chuck Lever III
2024-07-03 14:18 ` Christoph Hellwig
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