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Date: Mon, 17 Oct 2011 14:21:38 +0800
From: Chen Gong <gong.chen@linux.intel.com>
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To: Seiji Aguchi <seiji.aguchi@hds.com>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Luck, Tony" <tony.luck@intel.com>, Don Zickus <dzickus@redhat.com>,
        Matthew Garrett <mjg@redhat.com>, Vivek Goyal <vgoyal@redhat.com>,
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	<dle-develop@lists.sourceforge.net>,
        Satoru Moriya <satoru.moriya@hds.com>
Subject: Re: [RFC][PATCH -next] make pstore/kmsg_dump run after stopping other
 cpus in panic path
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于 2011/10/15 4:53, Seiji Aguchi 写道:
> Hi,
>
>   As Don mentioned in following thread, it would be nice for pstore/kmsg_dump to serialize
>   panic path and have one cpu running because they can log messages reliably.
>
>   https://lkml.org/lkml/2011/10/13/427
>
>   For realizing this idea, we have to move kmsg_dump below smp_send_stop() and bust some locks
>   of kmsg_dump/pstore in panic path.
>
>   This patch does followings.
>
>    - moving kmsg_dump(KMSG_DUMP_PANIC) below smp_send_stop.
>    - busting logbuf_lock of kmsg_dump() in panic path for avoiding deadlock.
>    - busting psinfo->buf_lock of pstore_dump() in panic path for avoiding deadlock.
>
> Any comments are welcome.
>

Hi, Seiji

I have a stupid question: since you have serialized the process procedure via 
smp_send_stop, why still using spin_lock_xxx? Maybe preempt_disable/enable is 
enough?