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Date: Wed, 20 Oct 2010 12:43:24 -0400
From: Jason Baron <jbaron@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>, LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        masami.hiramatsu.pt@hitachi.com
Subject: Re: [PATCH][GIT PULL] tracing: Fix compile issue for
	trace_sched_wakeup.c
Message-ID: <20101020164324.GC7348@redhat.com>
References: <1287508282.16971.386.camel@gandalf.stny.rr.com> <20101019184111.GA17266@elte.hu> <20101020154045.GA18353@elte.hu>
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On Wed, Oct 20, 2010 at 05:40:45PM +0200, Ingo Molnar wrote:
> FYI, there's a new mystery hang (sometimes crash) that triggers in -tip - and which 
> seems to be tracing related. See the crashlog below - config attached.
> 
> It's not bisectable - small changes in the kernel make the bug come/go. (might be a 
> race of some sorts)
> 
> Thanks,
> 
> 	Ingo
> 

strange b/c it looks like we get though enabling/disabling the
tracepoitns individually, but then when we go to enable all the
tracepoints we hit this hang - perhaps, suggesting a race. Do we always
fail after "Testing all events:" is printed? Does the crash have any
more clues. I will try and re-produce this.

Also, I noticed some recent changes to text_poke_smp() usage of
stop_machine() on Oct. 14th. That's related to the area where this appears
to hang, so if things were working with this .config before then, that
might be a place to look. Adding Masami to the 'cc list.

thanks,

-Jason