drm: Fix use-after-free in drm_gem_vm_close()

Commit Message

Chris Wilson March 17, 2011, 10:33 p.m. UTC

None

Patch

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 57ce27c..74e4ff5 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -499,11 +499,12 @@  EXPORT_SYMBOL(drm_gem_vm_open);
 void drm_gem_vm_close(struct vm_area_struct *vma)
 {
 	struct drm_gem_object *obj = vma->vm_private_data;
+	struct drm_device *dev = obj->dev;
 
-	mutex_lock(&obj->dev->struct_mutex);
+	mutex_lock(&dev->struct_mutex);
 	drm_vm_close_locked(vma);
 	drm_gem_object_unreference(obj);
-	mutex_unlock(&obj->dev->struct_mutex);
+	mutex_unlock(&dev->struct_mutex);
 }
 EXPORT_SYMBOL(drm_gem_vm_close);