From: Al Viro <viro@ZenIV.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: 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 13:24:51 +0100 [thread overview]
Message-ID: <20161029122451.GQ19539@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1477727070-18806-2-git-send-email-hch@lst.de>
On Sat, Oct 29, 2016 at 09:44:29AM +0200, Christoph Hellwig wrote:
> - if (rw == WRITE)
> + if (rw == WRITE) {
> file_start_write(file);
> + req->ki_flags |= IOCB_WRITE;
> + }
> + if (rw == WRITE) {
> + /*
> + * We release freeze protection in aio_complete(). Fool
> + * lockdep by telling it the lock got released so that
> + * it doesn't complain about held lock when we return
> + * to userspace.
> + */
> + __sb_writers_release(file_inode(file)->i_sb,
> + SB_FREEZE_WRITE);
> + }
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?
As it is, you risk hiding the lock dependencies the current mainline would've
caught. Other than that I see no problems with the patch...
next prev parent reply other threads:[~2016-10-29 12:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1477727070-18806-1-git-send-email-hch@lst.de>
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 [this message]
2016-10-29 15:20 ` Christoph Hellwig
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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