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Date: Tue, 16 Jun 2009 10:50:28 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       LKML <linux-kernel@vger.kernel.org>
Subject: Re: bug in tty ldisc and friends
Message-ID: <20090616085028.GA13771@elte.hu>
References: <alpine.DEB.2.00.0906160144340.26673@gandalf.stny.rr.com> <20090616093741.0d5b36bc@lxorguk.ukuu.org.uk>
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* Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> On Tue, 16 Jun 2009 01:45:36 -0400 (EDT)
> Steven Rostedt <rostedt@goodmis.org> wrote:
> 
> > [ Ingo and Andrew, sorry for the repost, but I forgot to Cc LKML and I 
> >   also used Alan's old email. ]
> > 
> > I can easily trigger a bug in the tty code by enabling the event 
> > tracers.
> 
> Yes I know. I sent Linus a temporary workaround yesterday. The bug 
> is as old as the hills (the race in various forms predates any git 
> or bk history!). The ldisc changes happened to make it more 
> visible.
>
> Unfortunately its non trivial to fix but the workaround should 
> make it as hard to hit now as in 2.6.30 while I sort the funnies 
> out. Really though I need the lock verifier working to do that, 
> and its been busted since 2.6.30 8(

Hm, have you tried the patch i sent to you that extends the 
number-lock-locks-tracked limit you have run into? It is trivial.

	Ingo