From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Theodore Ts'o <tytso@mit.edu>,
syzbot <syzbot+cdee56dbcdf0096ef605@syzkaller.appspotmail.com>,
adilger.kernel@dilger.ca, chandan.babu@oracle.com, jack@suse.com,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: current->journal_info got nested! (was Re: [syzbot] [xfs?] [ext4?] general protection fault in jbd2__journal_start)
Date: Tue, 30 Jan 2024 22:17:58 -0800 [thread overview]
Message-ID: <ZbnmFo0_dh-2Sgwl@infradead.org> (raw)
In-Reply-To: <Zbnicfk+JHIlG2WC@dread.disaster.area>
On Wed, Jan 31, 2024 at 05:02:25PM +1100, Dave Chinner wrote:
> This may not be true for other filesystems, but I don't think we
> can really say "page faults in any filesystem transaction are unsafe
> and should be banned"....
I think the point is page faults with current->journal_info set is
unsafe, as the can recurse into another file system using it. If we
don't set current->journal_info (and your ideas for that sound sensible
to me), the question of page faults in transactions is decoupled from
that. We just need to ensure we never recurse into a transaction in
the same or a dependent fs, which ot me suggest we'd better avoid it
if we easily can.
next prev parent reply other threads:[~2024-01-31 6:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-26 9:05 [syzbot] [ext4?] general protection fault in jbd2__journal_start syzbot
2024-01-30 14:52 ` [syzbot] [xfs?] " syzbot
2024-01-30 23:37 ` current->journal_info got nested! (was Re: [syzbot] [xfs?] [ext4?] general protection fault in jbd2__journal_start) Dave Chinner
2024-01-31 3:46 ` Darrick J. Wong
2024-01-31 4:58 ` Theodore Ts'o
2024-01-31 5:20 ` Matthew Wilcox
2024-01-31 5:47 ` Christoph Hellwig
2024-01-31 6:02 ` Dave Chinner
2024-01-31 6:17 ` Christoph Hellwig [this message]
2024-01-31 12:02 ` Jan Kara
2024-01-31 12:04 ` [PATCH] jbd2: user-memory-access in jbd2__journal_start Edward Adam Davis
2024-01-31 15:41 ` Jan Kara
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