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From: Ingo Molnar <mingo@elte.hu>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Greg KH <greg@kroah.com>, "Theodore Ts'o" <tytso@mit.edu>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: printk() vs tty_io
Date: Wed, 14 Dec 2011 07:59:10 +0100	[thread overview]
Message-ID: <20111214065910.GA25775@elte.hu> (raw)
In-Reply-To: <1323804803.9082.40.camel@twins>

* Peter Zijlstra <peterz@infradead.org> wrote:

> Hi tty folks,
> 
> I've been poking at reducing the constraints on printk(), like make it
> work under rq->lock etc..
> 
> Aside from a fwd port of the patch that abuses the 
> console_sem.lock: https://lkml.org/lkml/2011/6/9/298 and a few 
> other not so very pretty patches, I ran into the following 
> lockdep splat (using a not so very pretty lockdep 
> early_printk() patch):

btw., would be nice to also somehow realeasify those debug hacks 
to preserve them for eternity - doing all lockdep output as 
earlyprintk while keeping printks working is a great way to 
debug printk() itself.

Those printk lockups also took a *lot* of time for me to bisect.

Thanks,

	Ingo

  parent reply	other threads:[~2011-12-14  7:01 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-13 19:33 printk() vs tty_io Peter Zijlstra
2011-12-13 23:52 ` Linus Torvalds
2011-12-14  9:38   ` Peter Zijlstra
2011-12-14 10:43   ` Alan Cox
2011-12-14 10:56     ` Peter Zijlstra
2011-12-14 14:05       ` Ted Ts'o
2011-12-14 14:23         ` Peter Zijlstra
2011-12-14 15:54           ` Linus Torvalds
2011-12-15  9:56             ` Peter Zijlstra
2011-12-15 10:32               ` Alan Cox
2011-12-15 10:55                 ` Peter Zijlstra
2011-12-15 17:08               ` Linus Torvalds
2011-12-15 18:07                 ` Ingo Molnar
2011-12-15 21:22                 ` Alan Cox
2011-12-16 13:25                 ` Peter Zijlstra
2011-12-15 19:02               ` Greg KH
2011-12-14  6:59 ` Ingo Molnar [this message]
2011-12-14  9:40   ` [PATCH] arch, early_printk: Consolidate early_printk() implementations Peter Zijlstra
2011-12-14  9:41   ` [PATCH] lockdep: Enable earlyprintk output Peter Zijlstra
2011-12-14  9:43   ` printk() vs tty_io Peter Zijlstra
2011-12-14  9:46     ` Ingo Molnar
2011-12-21 12:03 ` Stijn Devriendt

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