Re: mmotm 2010-07-27 - nouveau lockdep issues.

From: Marcin Slusarz
Date: Wed Jul 28 2010 - 02:07:05 EST


On Wed, Jul 28, 2010 at 01:42:03AM -0400, Valdis.Kletnieks@xxxxxx wrote:
> On Tue, 27 Jul 2010 14:56:50 PDT, akpm@xxxxxxxxxxxxxxxxxxxx said:
> > The mm-of-the-moment snapshot 2010-07-27-14-56 has been uploaded to
> >
> > http://userweb.kernel.org/~akpm/mmotm/
>
> Hit this while the X server was on its way down during a 'shutdown -r now'. Worked fine
> in -rc5-mmotm0719. 'e16' is the Enlightenment window manager, if that matters.
>
> [ 93.181787] [drm:output_poll_execute] *ERROR* delayed enqueue failed 1
> [ 99.802836] [drm] nouveau 0000:01:00.0: Allocating FIFO number 4
> [ 99.808875] [drm] nouveau 0000:01:00.0: nouveau_channel_alloc: initialised FIFO 4
> [ 103.262226] [drm:output_poll_execute] *ERROR* delayed enqueue failed 1
> [ 113.341948] [drm:output_poll_execute] *ERROR* delayed enqueue failed 1
> [ 123.421836] [drm:output_poll_execute] *ERROR* delayed enqueue failed 1
> [ 123.550520] [drm] nouveau 0000:01:00.0: nouveau_channel_free: freeing fifo 4
> [ 123.551253]
> [ 123.551253] ======================================================
> [ 123.551253] [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ]
> [ 123.551253] 2.6.35-rc6-mmotm0727 #1
> [ 123.551253] ------------------------------------------------------
> [ 123.551253] e16/3822 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
> [ 123.551253] (&(&mm->unused_lock)->rlock){+.+...}, at: [<ffffffff812a94bc>] drm_mm_put_block+0x10e/0x142
> [ 123.551253]
> [ 123.551253] and this task is already holding:
> [ 123.551253] (&(&dev_priv->context_switch_lock)->rlock){-.....}, at: [<ffffffff812bdbab>] nouveau_channel_free+0x10f/0x233
> [ 123.551253] which would create a new lock dependency:
> [ 123.551253] (&(&dev_priv->context_switch_lock)->rlock){-.....} -> (&(&mm->unused_lock)->rlock){+.+...}
> [ 123.551253]

It's only theoritcal issue. If you want to quiet it down until it will be "fixed" properly, you can
apply patch from http://lists.freedesktop.org/archives/nouveau/2010-July/005994.html

Marcin

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