From: Jan Kara <jack@suse.cz>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: jack@suse.cz, linux-fsdevel@vger.kernel.org
Subject: Re: [2.6.32 ubuntu] I/O hang at start_this_handle
Date: Tue, 12 Apr 2011 21:50:51 +0200 [thread overview]
Message-ID: <20110412195051.GG5246@quack.suse.cz> (raw)
In-Reply-To: <201104091121.BFC34844.OHLtMOJVFFOSQF@I-love.SAKURA.ne.jp>
On Sat 09-04-11 11:21:40, Tetsuo Handa wrote:
> Jan Kara wrote:
> > Hmm, but 2.6.18 is really ancient. I'm afraid I cannot help you much with
> > it. There have been numerous bugs fixed since then.
>
> It is RHEL5.6 kernel which the known bugs have been fixed. I guess that RHEL6.0
Yes, but RHEL (as well as SLES) kernels are generally fixed on as needed
basis - i.e., when a customer reports an error, support debugs it and adds
the fix to the kernel. So you could well be the first one to spot the issue
with RHEL 5.6 kernel...
> kernel also has this bug (since this bug is in Ubuntu 10.04 kernels).
Yes, Ubuntu 10.04 is more relevant. 2.6.32 is not that old and I don't
remember any fixes in that area.
> So, I want to try establishing the steps to reproduce.
>
> Does anybody come up with common characteristics between below hangups?
>
> (a) Updating rpm packages using rpm executed from zypper.
>
> Although, the process actually hanged is /bin/sh which
> I guess was invoked for pre- or post- install scripts.
>
> Installing: grub-0.97-173.6 [91%]
>
> (b) Logging in from console using /bin/login .
>
> Although, the process actually hanged seems to be auditd process
> which attempted to write an audit log immediately after login event.
>
> (c) PostgreSQL and Apache.
>
> http://www.mail-archive.com/pgsql-bugs@postgresql.org/msg24852.html
>
> Writing with O_SYNC? Or calling fsync()? Or calling ftruncate()? Or ...?
I wouldn't expect any of this. If your original Ubuntu 10.04 report is
right, we block on j_barrier_count which is changed only in
journal_lock/unlock_updates() which gets called only from a few places.
The problem is that the hung process need not be directly related to the
hang. It can be just a victim of a race with some other process
manipulating j_barrier_count. But I don't see any such race in the code.
So I'd need a way to reproduce this so that we can perform some debugging.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
next prev parent reply other threads:[~2011-04-12 19:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-08 5:26 [2.6.32 ubuntu] I/O hang at start_this_handle Tetsuo Handa
2011-02-15 15:16 ` Jan Kara
2011-02-15 21:52 ` Tetsuo Handa
2011-02-16 15:53 ` Jan Kara
2011-02-17 8:13 ` Tetsuo Handa
2011-02-17 15:38 ` Jan Kara
2011-04-08 14:38 ` Tetsuo Handa
2011-04-08 18:29 ` Jan Kara
2011-04-09 2:21 ` Tetsuo Handa
2011-04-12 19:50 ` Jan Kara [this message]
2011-04-12 22:00 ` Tetsuo Handa
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