Re: i915_driver_irq_handler - BUG: NULL pointer dereference

From: Thomas Gleixner
Date: Wed Jul 22 2009 - 09:04:11 EST




On Wed, 22 Jul 2009, John Kacur wrote:

> Hello Thomas et al
>
> I'm still seeing this sometimes, in this case during shutdown with the experimental rt kernel
> based off of 2.6.31-rc3
>
> The system is going down for reboot NOW!
> Disabling monthly Smolt update: [ OK ]
> Shutting down Avahi daemon: [drm:gm45_get_vblank_counter] *ERROR* trying to get1
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000084
> IP: [<ffffffffa05df8ef>] i915_driver_irq_handler+0x848/0x8e9 [i915]

So it crashes in the i915 interrupt handler. Smells like a
synchronization problem on shutdown which is exposed by the threaded
handler.

Dave, any idea ?

Thanks,

tglx
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