netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Colin Ian King <colin.king@canonical.com>
To: netdev@vger.kernel.org
Cc: Thomas Graf <tgraf@suug.ch>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: rhashtable concurrent writers issue, 4.2+
Date: Fri, 11 Dec 2015 16:09:04 +0000	[thread overview]
Message-ID: <566AF520.4000904@canonical.com> (raw)

Hi,

After testing with commit 7def0f952eccdd0edb3c504f4dab35ee0d3aba1f
("lib: fix data race in rhashtable_rehash_one") on the current 4.4-rc4
kernel, I believe I am still seeing race conditions that seem to bite
concurrent readers.

The reproducer is found in my stress-ng system stress tool:

git://kernel.ubuntu.com/cking/stress-ng.git

one needs libattr1-dev, libkeyutils-dev to build this.

run the concurrent procfs stressor on 2 CPUs:

./stress-ng --procfs 2

..sometimes this hangs w/o a kernel stack dump, but sometimes it oopses
and one can see that we get a concurrent reader failure.

Colin

                 reply	other threads:[~2015-12-11 16:09 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

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=566AF520.4000904@canonical.com \
    --to=colin.king@canonical.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=tgraf@suug.ch \
    /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).