From: Janusz Krzysztofik Date: Fri, 5 Apr 2019 13:02:34 +0000 (+0200) Subject: drm/i915: Use drm_dev_unplug() X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~2467^2~26^2~207 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=d69990e0c399e4f7f9b50505d3285e5de991148a;p=mirror_ubuntu-focal-kernel.git drm/i915: Use drm_dev_unplug() The driver does not currently support unbinding from a device which is in use. Since open file descriptors may still be pointing into kernel memory where the device structures used to be, entirely correct kernel panics protect the driver from being unbound as we should not be unbinding it before those dangling pointers have been made safe. According to the documentation found inside drivers/gpu/drm/drm_drv.c, drm_dev_unplug() should be used instead of drm_dev_unregister() in order to make a device inaccessible to users as soon as it is unpluged. Follow that advice to make those possibly dangling pointers safe, protected by DRM layer from a user who is otherwise left pointing into possibly reused kernel memory after the driver has been unbound from the device. Once done, also cancel inflight operations immediately by calling i915_gem_set_wedged(). Signed-off-by: Janusz Krzysztofik Reviewed-by: Chris Wilson Reviewed-by: Daniel Vetter Signed-off-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20190405130235.7707-2-janusz.krzysztofik@linux.intel.com --- diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 1ad88e6d7c04..5e2ae2300454 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -1760,7 +1760,7 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv) i915_pmu_unregister(dev_priv); i915_teardown_sysfs(dev_priv); - drm_dev_unregister(&dev_priv->drm); + drm_dev_unplug(&dev_priv->drm); i915_gem_shrinker_unregister(dev_priv); }