[PATCH 0/2] console_lock debug improvements

From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: LKML <linux-kernel@vger.kernel.org>
Cc: DRI Development <dri-devel@lists.freedesktop.org>,
	linux-fbdev@vger.kernel.org, Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: [PATCH 0/2] console_lock debug improvements
Date: Wed, 22 Aug 2012 00:34:30 +0200	[thread overview]
Message-ID: <1345588472-4055-1-git-send-email-daniel.vetter@ffwll.ch> (raw)

Hi all,

After Dave Airlie blew through a few days to track down a deadlock at boot-up
when handing over from the firmware fb to the kms/drm framebuffer driver (1), I've
figured that lockdep /should/ have caught this.

And indeed, by adding proper annotations to the console_lock it complains about
the potential deadlock when exercising the entire driver life-cycle of just one
fb driver (i.e. not even a handover required). While at it, I've replaced the
existing in_interrupt check with the more paranoid might_sleep.

Comments, flames and review highly welcome.

Yours, Daniel

[1]: https://lkml.org/lkml/2012/8/21/36

Daniel Vetter (2):
  console: use might_sleep in console_lock
  console: implement lockdep support for console_lock

 kernel/printk.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

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1.7.10.4