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Commit 2368ffb1 authored by Mario Kleiner's avatar Mario Kleiner Committed by Daniel Vetter
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drm: Use vblank_disable_and_save in drm_vblank_cleanup() 



Calling vblank_disable_fn() will cause that function to no-op
if !dev->vblank_disable_allowed for some kms drivers, e.g.,
on nouveau-kms. This can cause the gpu vblank irq's to not get
disabled before freeing the dev->vblank array, so if a
vblank irq fires and calls into drm_handle_vblank() after
drm_vblank_cleanup() completes, it will cause use-after-free
access to dev->vblank array.

Call vblank_disable_and_save unconditionally, so vblank irqs
are guaranteed to be off, before we delete the data structures
on which they operate.

Signed-off-by: default avatarMario Kleiner <mario.kleiner.de@gmail.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Fix subsystem name in patch subject.]
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 79a093ae

drivers/gpu/drm/drm_irq.c

+5 −1
Original line number Diff line number Diff line
@@ -239,6 +239,7 @@ static void vblank_disable_fn(unsigned long arg) 
void drm_vblank_cleanup(struct drm_device *dev)

{

	int crtc;

	unsigned long irqflags;



	/* Bail if the driver didn't call drm_vblank_init() */

	if (dev->num_crtcs == 0)
@@ -248,7 +249,10 @@ void drm_vblank_cleanup(struct drm_device *dev) 
		struct drm_vblank_crtc *vblank = &dev->vblank[crtc];



		del_timer_sync(&vblank->disable_timer);

		vblank_disable_fn((unsigned long)vblank);



		spin_lock_irqsave(&dev->vbl_lock, irqflags);

		vblank_disable_and_save(dev, crtc);

		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);

	}



	kfree(dev->vblank);