On Tuesday, December 6, 2016 8:59:09 AM EST Christian König wrote:
> 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>.
>
Worked fine, fixed the issue for me.
Tested-by: Shawn Starr <shawn.starr at rogers.com>
> _______________________________________________
> amd-gfx mailing list
> amd-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
