Date: Wed, 20 Aug 2008 10:50:35 -0400
From: Josh Boyer <jwboyer@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
       Eran Liberty <liberty@extricom.com>,
       Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org,
       Steven Rostedt <srostedt@redhat.com>, Alan Modra <amodra@au1.ibm.com>,
       Scott Wood <scottwood@freescale.com>,
       "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
       segher@kernel.crashing.org
Subject: Re: ftrace introduces instability into kernel 2.6.27(-rc2,-rc3)
Message-ID: <20080820105035.49f29509@zod.rchland.ibm.com>
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On Wed, 20 Aug 2008 10:22:49 -0400 (EDT)
Steven Rostedt <rostedt@goodmis.org> wrote:

> 
> On Wed, 20 Aug 2008, Josh Boyer wrote:
> > 
> > Segher was looking at this a bit this morning.  He thinks it's really
> > -fno-omit-frame-pointer that is causing this.  That really shouldn't
> > even be set on PowerPC, but FTRACE uses select which overrides the
> > depends on stuff in Kconfig.
> 
> I can easily make a patch that makes that select an x86 only.

That's probably a first step, but you might want to wait until Segher
can fill in more details.  I'm sort of just relaying what he and I were
talking about on IRC.  IIRC, he was testing builds with and without
both -pg and -fno-omit-frame-pointer and found the bug only when
-fno-omit-frame-pointer was present.

josh
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