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Date: Wed, 18 Oct 2017 10:07:18 +0900
From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: pierre kuo <vichy.kuo@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>, rostedt@goodmis.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC V2] printk: add warning while drop partial text in msg
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On (10/18/17 01:10), pierre kuo wrote:
[..]
> > Well, it might get quite complicated, see printk_safe_flush_buffer().
> 
> BTW,  after checking printk_safe_flush_buffer() and related functions,
> we have one question:
> a) Why in printk_safe_log_store(), we need to use  atomic_xxxx operation in it?

because IRQ flush work iterates all CPUs and modifies CPUs' buffer state,
and this easily can race with printk_safe() or printk_nmi() on some of the
CPUs.

	-ss