From: Shaohua Li <shli@fb.com>
To: Christoph Hellwig <hch@lst.de>
Cc: neilb@suse.de, dan.j.williams@intel.com,
linux-raid@vger.kernel.org, Kernel-team@fb.com,
Song Liu <songliubraving@fb.com>
Subject: Re: fix use after free in raid5-cache
Date: Wed, 2 Sep 2015 09:55:24 -0700 [thread overview]
Message-ID: <20150902165522.GA2792971@devbig257.prn2.facebook.com> (raw)
In-Reply-To: <1441203288-22515-1-git-send-email-hch@lst.de>
On Wed, Sep 02, 2015 at 04:14:45PM +0200, Christoph Hellwig wrote:
> Hi Shaohua, hi Neil,
>
> this series fixes a use after free of the r5l_io_unit structure I ran into
> while testing the caching code. The real fix is in patch 3, but other two
> patches contain refactoring to enable the fix.
Hi Christoph,
Thanks for looking at it. I had some patches hold on my side, which fix
the use after free issue too. I changed the io_unit list handling a
little bit. Specifically making r5l_flush_stripe_to_raid run flush in
asynchronous way and also fix io_unit free issue.
For this patch set, the 1st is a good cleanup. I think the 2 & 3 have
the same issue changing the list order. For example, io_unit A is
dispatched to log earlier than io_unit B, but io_unit B can finish
earlier than io_unit A. If we move io_unit B to io_end_ios first, and
there is a crash, the metadata of io_unit A could be corrupt, recovery
can't find io_unit B. Please see the comments at
r5l_flush_stripe_to_raid().
I can rebase the 1st against my patches, what do you think?
Thanks,
Shaohua
next prev parent reply other threads:[~2015-09-02 16:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-02 14:14 fix use after free in raid5-cache Christoph Hellwig
2015-09-02 14:14 ` [PATCH 1/3] raid5-cache: move functionality out of __r5l_set_io_unit_state Christoph Hellwig
2015-09-02 14:14 ` [PATCH 2/3] raid5-cache: remove r5l_move_io_unit_list Christoph Hellwig
2015-09-02 14:14 ` [PATCH 3/3] raid5-cache: fix __r5l_stripe_write_finished Christoph Hellwig
2015-09-02 16:55 ` Shaohua Li [this message]
2015-09-02 17:22 ` fix use after free in raid5-cache Christoph Hellwig
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