From: Christoph Hellwig <hch@infradead.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Theodore Ts'o <tytso@mit.edu>, Dave Chinner <david@fromorbit.com>,
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 21:47:41 -0800 [thread overview]
Message-ID: <Zbne_dN3i85JjPxw@infradead.org> (raw)
In-Reply-To: <ZbnYitvLz7sWi727@casper.infradead.org>
On Wed, Jan 31, 2024 at 05:20:10AM +0000, Matthew Wilcox wrote:
> I'd suggest that saving off current->journal_info is risky because
> it might cover a real problem where you've taken a pagefault inside
> a transaction (eg ext4 faulting while in the middle of a transaction on
> the same filesystem that contains the faulting file).
Agreed.
> Seems to me that we shouldn't be writing to userspace while in the
> middle of a transaction. We could even assert that in copy_to_user()?
That sounds useful, but also rather expensive.
next prev parent reply other threads:[~2024-01-31 5:47 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 [this message]
2024-01-31 6:02 ` Dave Chinner
2024-01-31 6:17 ` Christoph Hellwig
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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