Re: [lkp-developer] [drm] 75f6dfe3e6: BUG:unable_to_handle_kernel

From: Gabriel Krisman Bertazi
Date: Tue Jan 03 2017 - 22:42:12 EST


kernel test robot <xiaolong.ye@xxxxxxxxx> writes:

>
> on test machine: qemu-system-x86_64 -enable-kvm -m 320M
>
> caused below changes:
>

> [ 1.608985] mwave: mwavedd::mwave_init: Error: Failed to initialize
> [ 1.609295] Hangcheck: starting hangcheck timer 0.9.1 (tick is 180 seconds, margin is 60 seconds).
> [ 1.609913] [drm] radeon kernel modesetting enabled.
> [ 1.610407] BUG: unable to handle kernel NULL pointer dereference at 0000002c
> [ 1.610833] IP: [<8143c0ba>] drm_dev_register+0xe9/0x173
> [ 1.611131] *pdpt = 0000000000000000 *pde = f000ff53f000ff53
> [ 1.611427]

I believe this is already fixed by 6098909cf2d0 ("drm: Avoid NULL
dereference of drm_device.dev"). But right now the tip of the
drm-intel-nightly already includes that patch, so I'm not sure if the
test included it, I think not.

I gave it a try with the jobfile just to be sure on top of
drm-misc-next, and I couldn't reproduce the error anymore after applying
Chris' patch (but I could reproduce the Oops when trying only with my
patch).

Also, sorry for the noise and lesson learned about virtual devices :(

--
Gabriel Krisman Bertazi