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@xxxxxxx>
Regardless of the above,
Reviewed-by: Michel Dänzer <michel.daenzer@xxxxxxx>
--
Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
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