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Date: Tue, 27 May 2008 14:34:26 +0800
From: "Luming Yu" <luming.yu@gmail.com>
To: "Roland McGrath" <roland@redhat.com>
Subject: Re: [RFC PATCH] set TASK_TRACED before arch_ptrace code to fix a race
Cc: "Petr Tesarik" <ptesarik@suse.cz>, LKML <linux-kernel@vger.kernel.org>,
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On Tue, May 27, 2008 at 2:12 PM, Roland McGrath <roland@redhat.com> wrote:
>>  [<a00000010000a9f0>] skip_rbs_switch+0xe0/0x110
>>                                 sp=e000000141c9fe30 bsp=e000000141c90cf8
>>  [<a000000000010740>] __kernel_syscall_via_break+0x0/0x20
>>                                 sp=e000000141ca0000 bsp=e000000141c90cf8
>>  [<a0000001000971c0>] ptrace_stop+0xa0/0x3e0
>>                                 sp=e00000014716fdb0 bsp=e000000147160ca8
>>  [<a000000100097650>] ptrace_notify+0x150/0x1c0
>>                                 sp=e00000014716fdb0 bsp=e000000147160c88
>
> If this is a backtrace of a single thread on the same kernel stack, it has
> a stack depth of over 84MB.  You still need to follow the path inside

you are right, I just find outputs of two different thread are mixed!
Please just ignore the call trace above..