From: Peter Zijlstra <peterz@infradead.org>
To: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: LKML <linux-kernel@vger.kernel.org>,
DRI Development <dri-devel@lists.freedesktop.org>,
Dave Airlie <airlied@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: [PATCH 2/2] [RESEND] console: implement lockdep support for console_lock
Date: Mon, 24 Sep 2012 14:24:38 +0200 [thread overview]
Message-ID: <1348489478.11847.55.camel@twins> (raw)
In-Reply-To: <1348489027.11847.53.camel@twins>
On Mon, 2012-09-24 at 14:17 +0200, Peter Zijlstra wrote:
> On Tue, 2012-09-18 at 01:03 +0200, Daniel Vetter wrote:
> > - In the printk code there's a special trylock, only used to kick off
> > the logbuffer printk'ing in console_unlock. But all that happens
> > while lockdep is disable (since printk does a few other evil
> > tricks). So no issue there, either.
>
> Not particularly evil, just plain broken.
>
> See this series:
>
> http://marc.info/?l=linux-kernel&m=132446644123326&w=2
>
> In particular see patches 1-4. The problem with lockdep is that lockdep
> uses printk and printk's recursion stuff is utterly broken.
>
> Console drivers being on crack simply doesn't help :-) Note that I would
> never recommend drm/ksm to anybody who really cares about their console
> output.
Also, don't cross-post with a subscribe only list.
next prev parent reply other threads:[~2012-09-24 12:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-17 23:03 [PATCH 1/2] [RESEND] console: use might_sleep in console_lock Daniel Vetter
2012-09-17 23:03 ` [PATCH 2/2] [RESEND] console: implement lockdep support for console_lock Daniel Vetter
2012-09-18 7:33 ` Jani Nikula
2012-09-19 7:30 ` Daniel Vetter
2012-09-22 17:52 ` [PATCH] " Daniel Vetter
2012-09-22 20:06 ` [Intel-gfx] " Greg KH
2012-09-24 11:36 ` Daniel Vetter
2012-10-02 12:56 ` Daniel Vetter
2012-10-02 13:28 ` Greg KH
2012-10-02 13:31 ` Daniel Vetter
2012-09-24 12:17 ` [PATCH 2/2] [RESEND] " Peter Zijlstra
2012-09-24 12:24 ` Peter Zijlstra [this message]
2012-09-24 12:54 ` Daniel Vetter
2012-09-24 13:10 ` Peter Zijlstra
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