linux-kernel - [RFC][PATCH 0/7] improve printk reliability

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Date:	Wed, 21 Dec 2011 11:57:39 +0100
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ted Ts'o <tytso@....edu>, Greg KH <greg@...ah.com>,
	Ingo Molnar <mingo@...e.hu>,
	Thomas Gleixner <tglx@...utronix.de>, akpm@...ux-foundation.org
Cc:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: [RFC][PATCH 0/7] improve printk reliability

Hi,

So these are my current efforts to make my own console output more
reliable. I've hit every deadlock described in this series and a few
more.

With these patches applied I can printk() and WARN() from inside 
scheduler context and not have my machine deadlock, even without the 
aid of early_printk().

While I'll go an remove the sole printk() I found in the scheduler
so that we don't have to rely on the console doing this, it is good
to have a reliable console that can do this.

As it stands some of the patches, the semaphore one in particular,
are really too ugly to live so I won't push those but wanted to share
anyway.

Debugging this was 'fun', and I really hope to not have to do it
again :-)

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