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Date: Mon, 18 Oct 2010 03:36:24 +0200
From: Frederic Weisbecker <fweisbec@gmail.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Valdis.Kletnieks@vt.edu, Andrew Morton <akpm@linux-foundation.org>,
        Paul Mackerras <paulus@samba.org>, Ingo Molnar <mingo@elte.hu>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        linux-kernel@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>
Subject: Re: 2.6.36-rc5-mmotm0928 BUG while trying to ptrace a process
Message-ID: <20101018013622.GA21722@nowhere>
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On Mon, Oct 18, 2010 at 10:28:43AM +0900, KOSAKI Motohiro wrote:
> > On Wed, 2010-10-06 at 05:32 -0400, Valdis.Kletnieks@vt.edu wrote:
> > > Dell Latitude E6500,  Intel Core2 Duo P8700 CPU.
> > > 
> > > Have seen this three times now while trying to attach gdb to a hung Firefox
> > > process.
> > > 
> > > [20669.480674] BUG: unable to handle kernel NULL pointer dereference at 0000000000000100
> > > [20669.480682] IP: [<ffffffff810b8275>] __reserve_bp_slot+0x56/0x17d
> > 
> > Known issue I think, Frederic was looking into curing this.
> > 
> > Frederic, what's the current status of that?
> 
> mmotm1014 seems still have this issue. Frederic, can you please tell us
> current status if you are tracking this issue?


Peter has a pending queue for .37 which includes:

	[RFC][PATCH 3/7] perf, hw_breakpoint: Fix crash in hw_breakpoint creation

This patch should fix the issue (it depends on others in the queue).

What is mmotm1014 BTW? Because you should see this bug only in a tree
that has tip:/perf/core merged inside, like linux-next.

Thanks.