diff --git a/linux-core/drm_bo.c b/linux-core/drm_bo.c
index 1c0eebd0..b9a261d5 100644
--- a/linux-core/drm_bo.c
+++ b/linux-core/drm_bo.c
@@ -67,6 +67,9 @@ void drm_bo_add_to_pinned_lru(drm_buffer_object_t * bo)
 {
 	drm_mem_type_manager_t *man;
 
+	DRM_ASSERT_LOCKED(&bo->dev->struct_mutex);
+	DRM_ASSERT_LOCKED(&bo->mutex);
+
 	man = &bo->dev->bm.man[bo->pinned_mem_type];
 	list_add_tail(&bo->pinned_lru, &man->pinned);
 }
@@ -75,6 +78,8 @@ void drm_bo_add_to_lru(drm_buffer_object_t * bo)
 {
 	drm_mem_type_manager_t *man;
 
+	DRM_ASSERT_LOCKED(&bo->dev->struct_mutex);
+
 	if (!(bo->mem.mask & (DRM_BO_FLAG_NO_MOVE | DRM_BO_FLAG_NO_EVICT))
 	    || bo->mem.mem_type != bo->pinned_mem_type) {
 		man = &bo->dev->bm.man[bo->mem.mem_type];
@@ -134,6 +139,8 @@ static int drm_bo_add_ttm(drm_buffer_object_t * bo)
 	int ret = 0;
 	bo->ttm = NULL;
 
+	DRM_ASSERT_LOCKED(&bo->mutex);
+
 	switch (bo->type) {
 	case drm_bo_type_dc:
 		bo->ttm = drm_ttm_init(dev, bo->mem.num_pages << PAGE_SHIFT);
@@ -266,6 +273,8 @@ int drm_bo_wait(drm_buffer_object_t * bo, int lazy, int ignore_signals,
 	drm_fence_object_t *fence = bo->fence;
 	int ret;
 
+	DRM_ASSERT_LOCKED(&bo->mutex);
+
 	if (fence) {
 		drm_device_t *dev = bo->dev;
 		if (drm_fence_object_signaled(dev, fence, bo->fence_type, 0)) {
@@ -331,6 +340,8 @@ static void drm_bo_cleanup_refs(drm_buffer_object_t * bo, int remove_all)
 	drm_device_t *dev = bo->dev;
 	drm_buffer_manager_t *bm = &dev->bm;
 
+	DRM_ASSERT_LOCKED(&dev->struct_mutex);
+
 	atomic_inc(&bo->usage);
 	mutex_unlock(&dev->struct_mutex);
 	mutex_lock(&bo->mutex);
@@ -393,6 +404,8 @@ static void drm_bo_destroy_locked(drm_buffer_object_t * bo)
 	drm_device_t *dev = bo->dev;
 	drm_buffer_manager_t *bm = &dev->bm;
 
+	DRM_ASSERT_LOCKED(&dev->struct_mutex);
+
 	if (list_empty(&bo->lru) && bo->mem.mm_node == NULL &&
 	    list_empty(&bo->pinned_lru) && bo->pinned_node == NULL &&
 	    list_empty(&bo->ddestroy) && atomic_read(&bo->usage) == 0) {
@@ -415,6 +428,7 @@ static void drm_bo_destroy_locked(drm_buffer_object_t * bo)
 
 		atomic_dec(&bm->count);
 
+		BUG_ON(!list_empty(&bo->base.list));
 		drm_ctl_free(bo, sizeof(*bo), DRM_MEM_BUFOBJ);
 
 		return;
@@ -491,6 +505,8 @@ static void drm_bo_delayed_workqueue(struct work_struct *work)
 
 void drm_bo_usage_deref_locked(drm_buffer_object_t * bo)
 {
+	DRM_ASSERT_LOCKED(&bo->dev->struct_mutex);
+
 	if (atomic_dec_and_test(&bo->usage)) {
 		drm_bo_destroy_locked(bo);
 	}
@@ -501,6 +517,8 @@ static void drm_bo_base_deref_locked(drm_file_t * priv, drm_user_object_t * uo)
 	drm_buffer_object_t *bo =
 	    drm_user_object_entry(uo, drm_buffer_object_t, base);
 
+	DRM_ASSERT_LOCKED(&bo->dev->struct_mutex);
+
 	drm_bo_takedown_vm_locked(bo);
 	drm_bo_usage_deref_locked(bo);
 }
@@ -1462,11 +1480,14 @@ static int drm_bo_handle_validate(drm_file_t * priv, uint32_t handle,
 				  uint32_t flags, uint32_t mask, uint32_t hint,
 				  drm_bo_arg_reply_t * rep)
 {
+        struct drm_device *dev = priv->head->dev;
 	drm_buffer_object_t *bo;
 	int ret;
 	int no_wait = hint & DRM_BO_HINT_DONT_BLOCK;
 
+	mutex_lock(&dev->struct_mutex);
 	bo = drm_lookup_buffer_object(priv, handle, 1);
+	mutex_unlock(&dev->struct_mutex);
 	if (!bo) {
 		return -EINVAL;
 	}
@@ -1498,9 +1519,13 @@ static int drm_bo_handle_validate(drm_file_t * priv, uint32_t handle,
 static int drm_bo_handle_info(drm_file_t * priv, uint32_t handle,
 			      drm_bo_arg_reply_t * rep)
 {
+        struct drm_device *dev = priv->head->dev;
 	drm_buffer_object_t *bo;
 
+	mutex_lock(&dev->struct_mutex);
 	bo = drm_lookup_buffer_object(priv, handle, 1);
+	mutex_unlock(&dev->struct_mutex);
+
 	if (!bo) {
 		return -EINVAL;
 	}
@@ -1520,7 +1545,11 @@ static int drm_bo_handle_wait(drm_file_t * priv, uint32_t handle,
 	int no_wait = hint & DRM_BO_HINT_DONT_BLOCK;
 	int ret;
 
+        struct drm_device *dev = priv->head->dev;
+	mutex_lock(&dev->struct_mutex);
 	bo = drm_lookup_buffer_object(priv, handle, 1);
+	mutex_unlock(&dev->struct_mutex);
+
 	if (!bo) {
 		return -EINVAL;
 	}
@@ -2319,6 +2348,7 @@ static void drm_bo_takedown_vm_locked(drm_buffer_object_t * bo)
 	drm_local_map_t *map;
 	drm_device_t *dev = bo->dev;
 
+	DRM_ASSERT_LOCKED(&dev->struct_mutex);
 	if (list->user_token) {
 		drm_ht_remove_item(&dev->map_hash, &list->hash);
 		list->user_token = 0;
@@ -2344,6 +2374,7 @@ static int drm_bo_setup_vm_locked(drm_buffer_object_t * bo)
 	drm_local_map_t *map;
 	drm_device_t *dev = bo->dev;
 
+	DRM_ASSERT_LOCKED(&dev->struct_mutex);
 	list->map = drm_ctl_calloc(1, sizeof(*map), DRM_MEM_BUFOBJ);
 	if (!list->map)
 		return -ENOMEM;
diff --git a/linux-core/drm_fence.c b/linux-core/drm_fence.c
index 70baad9f..b5fc2235 100644
--- a/linux-core/drm_fence.c
+++ b/linux-core/drm_fence.c
@@ -129,11 +129,14 @@ void drm_fence_usage_deref_locked(drm_device_t * dev,
 {
 	drm_fence_manager_t *fm = &dev->fm;
 
+	DRM_ASSERT_LOCKED(&dev->struct_mutex);
+
 	if (atomic_dec_and_test(&fence->usage)) {
 		drm_fence_unring(dev, &fence->ring);
 		DRM_DEBUG("Destroyed a fence object 0x%08lx\n",
 			  fence->base.hash.key);
 		atomic_dec(&fm->count);
+		BUG_ON(!list_empty(&fence->base.list));
 		drm_ctl_free(fence, sizeof(*fence), DRM_MEM_FENCE);
 	}
 }
@@ -148,6 +151,7 @@ void drm_fence_usage_deref_unlocked(drm_device_t * dev,
 		if (atomic_read(&fence->usage) == 0) {
 			drm_fence_unring(dev, &fence->ring);
 			atomic_dec(&fm->count);
+			BUG_ON(!list_empty(&fence->base.list));
 			drm_ctl_free(fence, sizeof(*fence), DRM_MEM_FENCE);
 		}
 		mutex_unlock(&dev->struct_mutex);
@@ -448,15 +452,16 @@ int drm_fence_add_user_object(drm_file_t * priv, drm_fence_object_t * fence,
 
 	mutex_lock(&dev->struct_mutex);
 	ret = drm_add_user_object(priv, &fence->base, shareable);
-	mutex_unlock(&dev->struct_mutex);
 	if (ret)
-		return ret;
+		goto out;
+	atomic_inc(&fence->usage);
 	fence->base.type = drm_fence_type;
 	fence->base.remove = &drm_fence_object_destroy;
 	DRM_DEBUG("Fence 0x%08lx created\n", fence->base.hash.key);
-	return 0;
+out:
+	mutex_unlock(&dev->struct_mutex);
+	return ret;
 }
-
 EXPORT_SYMBOL(drm_fence_add_user_object);
 
 int drm_fence_object_create(drm_device_t * dev, uint32_t class, uint32_t type,
@@ -466,7 +471,7 @@ int drm_fence_object_create(drm_device_t * dev, uint32_t class, uint32_t type,
 	int ret;
 	drm_fence_manager_t *fm = &dev->fm;
 
-	fence = drm_ctl_alloc(sizeof(*fence), DRM_MEM_FENCE);
+	fence = drm_ctl_calloc(1, sizeof(*fence), DRM_MEM_FENCE);
 	if (!fence)
 		return -ENOMEM;
 	ret = drm_fence_object_init(dev, class, type, flags, fence);
@@ -566,13 +571,8 @@ int drm_fence_ioctl(DRM_IOCTL_ARGS)
 			drm_fence_usage_deref_unlocked(dev, fence);
 			return ret;
 		}
-
-		/*
-		 * usage > 0. No need to lock dev->struct_mutex;
-		 */
-
-		atomic_inc(&fence->usage);
 		arg.handle = fence->base.hash.key;
+
 		break;
 	case drm_fence_destroy:
 		mutex_lock(&dev->struct_mutex);
@@ -637,7 +637,6 @@ int drm_fence_ioctl(DRM_IOCTL_ARGS)
 						DRM_FENCE_FLAG_SHAREABLE);
 		if (ret)
 			return ret;
-		atomic_inc(&fence->usage);
 		arg.handle = fence->base.hash.key;
 		break;
 	default:
diff --git a/linux-core/drm_object.c b/linux-core/drm_object.c
index 03906034..567a7d2b 100644
--- a/linux-core/drm_object.c
+++ b/linux-core/drm_object.c
@@ -36,6 +36,8 @@ int drm_add_user_object(drm_file_t * priv, drm_user_object_t * item,
 	drm_device_t *dev = priv->head->dev;
 	int ret;
 
+	DRM_ASSERT_LOCKED(&dev->struct_mutex);
+
 	atomic_set(&item->refcount, 1);
 	item->shareable = shareable;
 	item->owner = priv;
@@ -56,6 +58,8 @@ drm_user_object_t *drm_lookup_user_object(drm_file_t * priv, uint32_t key)
 	int ret;
 	drm_user_object_t *item;
 
+	DRM_ASSERT_LOCKED(&dev->struct_mutex);
+
 	ret = drm_ht_find_item(&dev->object_hash, key, &hash);
 	if (ret) {
 		return NULL;
@@ -88,6 +92,8 @@ static void drm_deref_user_object(drm_file_t * priv, drm_user_object_t * item)
 
 int drm_remove_user_object(drm_file_t * priv, drm_user_object_t * item)
 {
+	DRM_ASSERT_LOCKED(&priv->head->dev->struct_mutex);
+
 	if (item->owner != priv) {
 		DRM_ERROR("Cannot destroy object not owned by you.\n");
 		return -EINVAL;
@@ -125,6 +131,7 @@ int drm_add_ref_object(drm_file_t * priv, drm_user_object_t * referenced_object,
 	drm_ref_object_t *item;
 	drm_open_hash_t *ht = &priv->refd_object_hash[ref_action];
 
+	DRM_ASSERT_LOCKED(&priv->head->dev->struct_mutex);
 	if (!referenced_object->shareable && priv != referenced_object->owner) {
 		DRM_ERROR("Not allowed to reference this object\n");
 		return -EINVAL;
@@ -181,6 +188,7 @@ drm_ref_object_t *drm_lookup_ref_object(drm_file_t * priv,
 	drm_hash_item_t *hash;
 	int ret;
 
+	DRM_ASSERT_LOCKED(&priv->head->dev->struct_mutex);
 	ret = drm_ht_find_item(&priv->refd_object_hash[ref_action],
 			       (unsigned long)referenced_object, &hash);
 	if (ret)
@@ -213,6 +221,7 @@ void drm_remove_ref_object(drm_file_t * priv, drm_ref_object_t * item)
 	drm_open_hash_t *ht = &priv->refd_object_hash[item->unref_action];
 	drm_ref_t unref_action;
 
+	DRM_ASSERT_LOCKED(&priv->head->dev->struct_mutex);
 	unref_action = item->unref_action;
 	if (atomic_dec_and_test(&item->refcount)) {
 		ret = drm_ht_remove_item(ht, &item->hash);
diff --git a/linux-core/drm_objects.h b/linux-core/drm_objects.h
index 42c8e536..59c8902d 100644
--- a/linux-core/drm_objects.h
+++ b/linux-core/drm_objects.h
@@ -473,4 +473,12 @@ extern int drm_bo_move_accel_cleanup(drm_buffer_object_t * bo,
 				     uint32_t fence_flags,
 				     drm_bo_mem_reg_t * new_mem);
 
+#ifdef CONFIG_DEBUG_MUTEXES
+#define DRM_ASSERT_LOCKED(_mutex)					\
+	BUG_ON(!mutex_is_locked(_mutex) ||				\
+	       ((_mutex)->owner != current_thread_info()))
+#else
+#define DRM_ASSERT_LOCKED(_mutex)
+#endif
+
 #endif