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

["Michel Dänzer" <michel-otUistvHUpPR7s880joybQ@public.gmane.org>]

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@amd.com>

Regardless of the above,

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer
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