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Date: Thu, 6 Apr 2017 19:20:52 +0200
From: Pavel Machek <pavel@ucw.cz>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>, Petr Mladek <pmladek@suse.com>,
        Jan Kara <jack@suse.cz>, Andrew Morton <akpm@linux-foundation.org>,
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        linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [RFC][PATCHv2 4/8] pm: switch to printk.emergency mode in unsafe
 places
Message-ID: <20170406172051.GC10363@amd>
References: <20170329092511.3958-1-sergey.senozhatsky@gmail.com>
 <20170329092511.3958-5-sergey.senozhatsky@gmail.com>
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On Wed 2017-03-29 18:25:07, Sergey Senozhatsky wrote:
> It's not always possible/safe to wake_up() printk kernel
> thread. For example, late suspend/early resume may printk()
> while timekeeping is not initialized yet, so calling into the
> scheduler may result in recursive warnings.
>=20
> Another thing to notice is the fact PM at some point
> freezes user space and kernel threads: freeze_processes()
> and freeze_kernel_threads(), correspondingly. Thus we need
> printk() to operate in old mode there and attempt to
> immediately flush pending kernel message to the console.
>=20
> This patch adds printk_emergency_begin/on sections.
>=20
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>

I don't like this. It is symptom of printk getting much more fragile
now.

								Pavel
--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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