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: Mario Kleiner mario.kleiner.de@gmail.com Cc: stable@vger.kernel.org --- drivers/gpu/drm/drm_irq.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 89e91e3..22e2bba9 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -164,6 +164,7 @@ 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) @@ -171,7 +172,9 @@ void drm_vblank_cleanup(struct drm_device *dev)
for (crtc = 0; crtc < dev->num_crtcs; crtc++) { del_timer_sync(&dev->vblank[crtc].disable_timer); - vblank_disable_fn((unsigned long)&dev->vblank[crtc]); + spin_lock_irqsave(&dev->vbl_lock, irqflags); + vblank_disable_and_save(dev, crtc); + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); }
kfree(dev->vblank);