linux-kernel - Re: BUG: enabling psacct breaks fsfreeze

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Message-ID: <20121101111957.GD6584@quack.suse.cz>
Date:	Thu, 1 Nov 2012 12:19:57 +0100
From:	Jan Kara <jack@...e.cz>
To:	Nikola Ciprich <nikola.ciprich@...uxbox.cz>
Cc:	Jan Kara <jack@...e.cz>, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: BUG: enabling psacct breaks fsfreeze

On Thu 01-11-12 10:37:23, Jan Kara wrote:
> On Wed 31-10-12 13:46:00, Nikola Ciprich wrote:
> > Hi Jan,
> > 
> > thanks for the reply, sure, I'll gather and post requested info.
> > One more note before that, the problem is with psacct, not audit
> >  - psacct if I'm not mistaken  (and as opposed to audit) doesn't
> > use any userspace, kernel dumps information directly to fs, 
> > which might the reason for deadlock..
>   Ah, right. Now I looked into the right code and I can see what's the
> problem. I'll see what we could do about that... So far I don't have a
> better idea than just dropping accounting records that should be written to
> frozen filesystem (as you have nowhere to write those records to).
  But I'd still be interested in those traces. I can see how one process
gets blocked but it's not quite clear on which locks do other block.

								Honza

> > > > Should more debugging information be needed, I'll be glad to provide whatever I can..
> > >   Thanks for report. Hum, I'm not sure how the deadlock can happen because
> > > AFAIU audit sends a message via netlink to userspace and whatever audit
> > > daemon does with it is its private thing. Can you please run:
> > >   echo w >/proc/sysrq-trigger
> > > after the machine deadlocks and then take dmesg and attach it here? You'll
> > > have to have the shell prepared and use serial console / netconsole to gather
> > > dmesg or try your luck with copying via ssh / netcat.
> > > 
> > > 								Honza
> > > -- 
> > > Jan Kara <jack@...e.cz>
> > > SUSE Labs, CR
> > > 
> > 
> > -- 
> > -------------------------------------
> > Ing. Nikola CIPRICH
> > LinuxBox.cz, s.r.o.
> > 28.rijna 168, 709 00 Ostrava
> > 
> > tel.:   +420 591 166 214
> > fax:    +420 596 621 273
> > mobil:  +420 777 093 799
> > www.linuxbox.cz
> > 
> > mobil servis: +420 737 238 656
> > email servis: servis@...uxbox.cz
> > -------------------------------------
> 
> 
> -- 
> Jan Kara <jack@...e.cz>
> SUSE Labs, CR
-- 
Jan Kara <jack@...e.cz>
SUSE Labs, CR
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