linux-ext4.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Eric Whitney <enwlinux@gmail.com>
To: linux-ext4@vger.kernel.org
Cc: tytso@mit.edu, willy@infradead.org
Subject: generic/418 regression seen on 5.12-rc3
Date: Thu, 18 Mar 2021 14:16:13 -0400	[thread overview]
Message-ID: <20210318181613.GA13891@localhost.localdomain> (raw)

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.

So, the failure isn't dependent upon block size less than page size.

Eric

             reply	other threads:[~2021-03-18 18:17 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-18 18:16 Eric Whitney [this message]
2021-03-18 19:41 ` generic/418 regression seen on 5.12-rc3 Theodore Ts'o
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=20210318181613.GA13891@localhost.localdomain \
    --to=enwlinux@gmail.com \
    --cc=linux-ext4@vger.kernel.org \
    --cc=tytso@mit.edu \
    --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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).