On Sat, Dec 03, 2016 at 03:47:00PM +0100, Nicolai Stange 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, radeon_debugfs_add_files() accesses
> ->control->debugfs_root though. This results in the following Oops:
>
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
> IP: radeon_debugfs_add_files+0x90/0x100 [radeon]
> PGD 0
> Oops: 0000 [#1] SMP
> [...]
> Call Trace:
> ? work_on_cpu+0xb0/0xb0
> radeon_fence_driver_init+0x120/0x150 [radeon]
> si_init+0x122/0xd50 [radeon]
> ? _raw_spin_unlock_irq+0x2c/0x40
> ? device_pm_check_callbacks+0xb3/0xc0
> radeon_device_init+0x958/0xda0 [radeon]
> radeon_driver_load_kms+0x9a/0x210 [radeon]
> drm_dev_register+0xa9/0xd0 [drm]
> drm_get_pci_dev+0x9c/0x1e0 [drm]
> radeon_pci_probe+0xb8/0xe0 [radeon]
> [...]
>
> Fix this by omitting the drm_debugfs_create_files() call for the
> control minor debugfs directory which is now non-existent anyway.
>
> Fixes: 8a357d10043c ("drm: Nerf DRM_CONTROL nodes")
> Signed-off-by: Nicolai Stange <nicstange@xxxxxxxxx>
Applied to drm-misc with Dave's irc ack, thanks for your patch.
-Daniel
> ---
> Tested on top of next-20161202.
> That 8a357d10043c ("drm: Nerf DRM_CONTROL nodes")
> is in next since 20161201.
>
> drivers/gpu/drm/radeon/radeon_device.c | 6 ------
> 1 file changed, 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
> index 60a8920..8a1df2a 100644
> --- a/drivers/gpu/drm/radeon/radeon_device.c
> +++ b/drivers/gpu/drm/radeon/radeon_device.c
> @@ -1949,9 +1949,6 @@ int radeon_debugfs_add_files(struct radeon_device *rdev,
> rdev->debugfs_count = i;
> #if defined(CONFIG_DEBUG_FS)
> drm_debugfs_create_files(files, nfiles,
> - rdev->ddev->control->debugfs_root,
> - rdev->ddev->control);
> - drm_debugfs_create_files(files, nfiles,
> rdev->ddev->primary->debugfs_root,
> rdev->ddev->primary);
> #endif
> @@ -1966,9 +1963,6 @@ static void radeon_debugfs_remove_files(struct radeon_device *rdev)
> for (i = 0; i < rdev->debugfs_count; i++) {
> drm_debugfs_remove_files(rdev->debugfs[i].files,
> rdev->debugfs[i].num_files,
> - rdev->ddev->control);
> - drm_debugfs_remove_files(rdev->debugfs[i].files,
> - rdev->debugfs[i].num_files,
> rdev->ddev->primary);
> }
> #endif
> --
> 2.10.2
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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