From: Christoph Hellwig <hch@lst.de>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>,
torvalds@linux-foundation.org, jack@suse.cz,
dmonakhov@openvz.org, jmoyer@redhat.com,
linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] aio: fix a user triggered use after free (and fix freeze protection of aio writes)
Date: Sat, 29 Oct 2016 17:20:17 +0200 [thread overview]
Message-ID: <20161029152017.GA7388@lst.de> (raw)
In-Reply-To: <20161029122451.GQ19539@ZenIV.linux.org.uk>
On Sat, Oct 29, 2016 at 01:24:51PM +0100, Al Viro wrote:
> How about taking this chunk (i.e. telling lockdep that we are not holding this
> thing) past the iter_op() call, where file_end_write() used to be?
We can't as that would not fix the use after free (at least for the lockdep
case - otherwise the call is a no-op). Once iter_op returns aio_complete
might have dropped our reference to the file, and another thread might
have closed the fd so that the fput from aio_complete was the last one.
This is something that xfstests/323 can reproduce under the right conditions.
next prev parent reply other threads:[~2016-10-29 15:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-29 7:44 aio: fix a user triggered use after free Christoph Hellwig
2016-10-29 7:44 ` [PATCH] aio: fix a user triggered use after free (and fix freeze protection of aio writes) Christoph Hellwig
2016-10-29 12:24 ` Al Viro
2016-10-29 15:20 ` Christoph Hellwig [this message]
2016-10-29 16:12 ` Al Viro
2016-10-29 16:29 ` Al Viro
2016-10-30 6:32 ` Christoph Hellwig
2016-10-29 17:47 ` Linus Torvalds
2016-10-29 18:52 ` Al Viro
2016-10-29 19:07 ` Linus Torvalds
2016-10-29 19:17 ` Al Viro
2016-10-29 20:09 ` Linus Torvalds
2016-10-30 9:44 ` Jan Kara
2016-10-30 10:52 ` Jan Kara
2016-10-30 15:58 ` Christoph Hellwig
2016-10-30 6:29 ` Christoph Hellwig
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