tree 2e283076bfb6efdb99aa24f8c92809e0333659f4
parent 692ef70c016b5035ad1942ccc2bc4040aa290044
author Ville Syrjälä <ville.syrjala@linux.intel.com> 1407322971 +0300
committer Daniel Vetter <daniel.vetter@ffwll.ch> 1407512638 +0200

drm/i915: Free pending page flip events at .preclose()

If there are pending page flips when the fd gets closed those page
flips may have events associated to them. When the page flip eventually
completes it will queue the event to file_priv->event_list, but that
may be too late and file_priv->event_list has already been cleaned up.
Thus we leak a bit of kernel memory in the form of the event structure.

To avoid such problems clear out such pending events from
intel_crtc->unpin_work at ->preclose(). Any event that already made it
to file_priv->event_list will get cleaned up by the drm_release_events()
a bit later.

We can ignore the file_priv->event_space accounting since file_priv is
going away. This is already how drm core deals with pending vblank
events, which are maintained by the drm core.

What saves us from a total disaster (ie. dereferencing and alrady
freed file_priv) is the fact that the fb descruction triggers a modeset
and there we wait for pending flips.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>