From: "Theodore Ts'o" <tytso@mit.edu>
To: Eric Whitney <enwlinux@gmail.com>
Cc: linux-ext4@vger.kernel.org, willy@infradead.org
Subject: Re: generic/418 regression seen on 5.12-rc3
Date: Thu, 18 Mar 2021 15:41:58 -0400 [thread overview]
Message-ID: <YFOtBqSR6wq41G1T@mit.edu> (raw)
In-Reply-To: <20210318181613.GA13891@localhost.localdomain>
On Thu, Mar 18, 2021 at 02:16:13PM -0400, Eric Whitney wrote:
> As mentioned in today's ext4 concall, I've seen generic/418 fail from time to
> time when run on 5.12-rc3 and 5.12-rc1 kernels. This first occurred when
> running the 1k test case using kvm-xfstests. I was then able to bisect the
> failure to a patch landed in the -rc1 merge window:
>
> (bd8a1f3655a7) mm/filemap: support readpage splitting a page
>
> Typical test output resulting from a failure looks like:
>
> QA output created by 418
> +cmpbuf: offset 0: Expected: 0x1, got 0x0
> +[6:0] FAIL - comparison failed, offset 3072
> +diotest -w -b 512 -n 8 -i 4 failed at loop 0
> Silence is golden
> ...
>
> I've also been able to reproduce the failure on -rc3 in the 4k test case as
> well. The failure frequency there was 10 out of 100 runs. It was anywhere
> from 2 to 8 failures out of 100 runs in the 1k case.
FWIW, testing on a kernel which is -rc2 based (ext4.git's tip) I
wasn't able to see a failure using gce-xfstests using the ext4/4k,
ext4/1k, and xfs/1k test scenarios. This may be because of the I/O
timing for the persistent disk block device in GCE, or differences in
the number of CPU's or amount of memory available --- or in the kernel
configuration that was used to build it.
I'm currently retrying with -rc3, with and without the kernel debug
configs, to see if that makes any difference...
- Ted
next prev parent reply other threads:[~2021-03-18 19:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 18:16 generic/418 regression seen on 5.12-rc3 Eric Whitney
2021-03-18 19:41 ` Theodore Ts'o [this message]
2021-03-18 20:15 ` Matthew Wilcox
2021-03-18 21:38 ` Eric Whitney
2021-03-18 22:16 ` Matthew Wilcox
2021-03-22 16:37 ` Eric Whitney
2021-03-28 2:41 ` Matthew Wilcox
2021-04-01 16:15 ` Jan Kara
2021-04-01 17:46 ` Eric Whitney
2021-04-02 5:07 ` Ritesh Harjani
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YFOtBqSR6wq41G1T@mit.edu \
--to=tytso@mit.edu \
--cc=enwlinux@gmail.com \
--cc=linux-ext4@vger.kernel.org \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.