We return immediately from i915_driver_register() if drm_dev_register() fails, skipping remaining registration steps. However, the _unregister() counterpart called at device remove knows nothing about that skip and executes reverts for all those steps. For that to work correctly, those revert functions must be resistant to being called even on uninitialized objects, or we must not skip their initialization.
If device sysfs setup is skipped then its teardown counterpart, unconditionally called when unregistering the driver, fails and emits a warning that taints the kernel: <3> [525.823143] i915 0000:00:02.0: [drm] *ERROR* Failed to register driver for userspace access! ... <4> [526.441186] ------------[ cut here ]------------ <4> [526.441191] kernfs: can not remove 'error', no directory <4> [526.441211] WARNING: CPU: 1 PID: 3440 at fs/kernfs/dir.c:1684 kernfs_remove_by_name_ns+0xbc/0xc0 ... <4> [526.441536] RIP: 0010:kernfs_remove_by_name_ns+0xbc/0xc0 ... <4> [526.441578] Call Trace: <4> [526.441581] <TASK> ... <4> [526.441686] sysfs_remove_bin_file+0x17/0x30 <4> [526.441691] i915_gpu_error_sysfs_teardown+0x1d/0x30 [i915] <4> [526.442226] i915_teardown_sysfs+0x1c/0x60 [i915] <4> [526.442369] i915_driver_remove+0x9d/0x140 [i915] <4> [526.442473] i915_pci_remove+0x1e/0x40 [i915] ... Since restoring symmetry by setting up the device sysfs even after a failure is not possible due to missing dependencies, teach the teardown counterpart to handle all components of the never set up device sysfs gently. Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/9820 Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/10131 Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/10887 Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12817 Signed-off-by: Janusz Krzysztofik <janusz.krzyszto...@linux.intel.com> --- drivers/gpu/drm/i915/i915_sysfs.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c index 8775beab9cb84..9758a7ca27fd2 100644 --- a/drivers/gpu/drm/i915/i915_sysfs.c +++ b/drivers/gpu/drm/i915/i915_sysfs.c @@ -189,6 +189,9 @@ void i915_teardown_sysfs(struct drm_i915_private *dev_priv) { struct device *kdev = dev_priv->drm.primary->kdev; + if (!dev_priv->sysfs_gt) + return; + i915_gpu_error_sysfs_teardown(dev_priv); device_remove_bin_file(kdev, &dpf_attrs_1); -- 2.47.1
