linux-ext4 - Re: [PATCH] ext4: Fix a race in the ext4 shutdown path.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20180110051403.GF5809@thunk.org>
Date:   Wed, 10 Jan 2018 00:14:03 -0500
From:   Theodore Ts'o <tytso@....edu>
To:     harshads <harshads@...gle.com>
Cc:     linux-ext4@...r.kernel.org
Subject: Re: [PATCH] ext4: Fix a race in the ext4 shutdown path.

On Tue, Jan 09, 2018 at 02:52:57PM -0800, harshads wrote:
> This patch fixes a race between the shutdown path and bio completion
> handling. In the ext4 direct io path with async io, after submitting a
> bio to the block layer, if journal starting fails,
> ext4_direct_IO_write() would bail out pretending that the IO
> failed. The caller would have had no way of knowing whether or not the
> IO was successfully submitted. So instead, we return -EIOCBQUEUED in
> this case. Now, the caller knows that the IO was submitted.  The bio
> completion handler takes care of the error.
> 
> Tested: Ran the shutdown xfstest test 461 in loop for over 2 hours across
> 4 machines resulting in over 400 runs. Verified that the race didn't
> occur. Usually the race was seen in about 20-30 iterations.
> 
> Signed-off-by: Harshad Shirwadkar <harshads@...gle.com>

Thanks, applied.

					- Ted