[PATCH] drm/amdgpu: don't add files at control minor debugfs directory

[Christian König]

Am 06.12.2016 um 02:00 schrieb Michel Dänzer:
> On 06/12/16 05:07 AM, Alex Deucher wrote:
>> Since commit 8a357d10043c ("drm: Nerf DRM_CONTROL nodes"), a
>> struct drm_device's ->control member is always NULL.
>>
>> In the case of CONFIG_DEBUG_FS=y, amdgpu_debugfs_add_files() accesses
>> ->control->debugfs_root though. This results in the following Oops:
>>
>> [    9.627636] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
>> [    9.628274] IP: amdgpu_debugfs_add_files+0x8d/0x100 [amdgpu]
>> [    9.628867] PGD 2514c7067
>> [    9.628876] PUD 2514c8067
>> [    9.629448] PMD 0
>> [    9.630026] Oops: 0000 [#1] PREEMPT SMP
>> [...]
>> [    9.639906] Call Trace:
>> [    9.640538]  amdgpu_fence_driver_init+0x1e/0x40 [amdgpu]
>> [    9.641186]  amdgpu_device_init+0xa6d/0x1410 [amdgpu]
>> [    9.641900]  ? kmalloc_order_trace+0x2e/0x100
>> [    9.642587]  amdgpu_driver_load_kms+0x5b/0x200 [amdgpu]
>> [    9.643355]  drm_dev_register+0xa7/0xd0
>> [    9.644016]  drm_get_pci_dev+0xde/0x1d0
>> [    9.644659]  amdgpu_pci_probe+0xbe/0xf0 [amdgpu]
>> [...]
>>
>> Fix this by omitting the drm_debugfs_create_files() call for the
>> control minor debugfs directory which is now non-existent anyway.
>>
>> Port of Nicolai Stange's radeon patch to amdgpu.
>>
>> bug: https://bugs.freedesktop.org/show_bug.cgi?id=98915
> Not sure about the kernel, but in other projects the convention is
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98915
>
>
>> Fixes: 8a357d10043c ("drm: Nerf DRM_CONTROL nodes")
>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> Regardless of the above,
>
> Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>

Reviewed-by: Christian König <christian.koenig at amd.com>.