diff --git a/drivers/gpu/drm/drm_auth.c b/drivers/gpu/drm/drm_auth.c
index 232abbba36868b425321ae02cb8b83351f5b3c74..c7adbeaf10b1b76545b8fbebcd01560a8bd6d772 100644
--- a/drivers/gpu/drm/drm_auth.c
+++ b/drivers/gpu/drm/drm_auth.c
@@ -135,16 +135,18 @@ static void drm_set_master(struct drm_device *dev, struct drm_file *fpriv,
 static int drm_new_set_master(struct drm_device *dev, struct drm_file *fpriv)
 {
 	struct drm_master *old_master;
+	struct drm_master *new_master;
 
 	lockdep_assert_held_once(&dev->master_mutex);
 
 	WARN_ON(fpriv->is_master);
 	old_master = fpriv->master;
-	fpriv->master = drm_master_create(dev);
-	if (!fpriv->master) {
-		fpriv->master = old_master;
+	new_master = drm_master_create(dev);
+	if (!new_master)
 		return -ENOMEM;
-	}
+	spin_lock(&fpriv->master_lookup_lock);
+	fpriv->master = new_master;
+	spin_unlock(&fpriv->master_lookup_lock);
 
 	fpriv->is_master = 1;
 	fpriv->authenticated = 1;
@@ -302,10 +304,13 @@ int drm_master_open(struct drm_file *file_priv)
 	/* if there is no current master make this fd it, but do not create
 	 * any master object for render clients */
 	mutex_lock(&dev->master_mutex);
-	if (!dev->master)
+	if (!dev->master) {
 		ret = drm_new_set_master(dev, file_priv);
-	else
+	} else {
+		spin_lock(&file_priv->master_lookup_lock);
 		file_priv->master = drm_master_get(dev->master);
+		spin_unlock(&file_priv->master_lookup_lock);
+	}
 	mutex_unlock(&dev->master_mutex);
 
 	return ret;
@@ -371,6 +376,31 @@ struct drm_master *drm_master_get(struct drm_master *master)
 }
 EXPORT_SYMBOL(drm_master_get);
 
+/**
+ * drm_file_get_master - reference &drm_file.master of @file_priv
+ * @file_priv: DRM file private
+ *
+ * Increments the reference count of @file_priv's &drm_file.master and returns
+ * the &drm_file.master. If @file_priv has no &drm_file.master, returns NULL.
+ *
+ * Master pointers returned from this function should be unreferenced using
+ * drm_master_put().
+ */
+struct drm_master *drm_file_get_master(struct drm_file *file_priv)
+{
+	struct drm_master *master = NULL;
+
+	spin_lock(&file_priv->master_lookup_lock);
+	if (!file_priv->master)
+		goto unlock;
+	master = drm_master_get(file_priv->master);
+
+unlock:
+	spin_unlock(&file_priv->master_lookup_lock);
+	return master;
+}
+EXPORT_SYMBOL(drm_file_get_master);
+
 static void drm_master_destroy(struct kref *kref)
 {
 	struct drm_master *master = container_of(kref, struct drm_master, refcount);
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 0ac4566ae3f450d5a7fdea59852c83a32c575db1..537e7de8e9c33520ff1c5812623b9a23ccdd3826 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -177,6 +177,7 @@ struct drm_file *drm_file_alloc(struct drm_minor *minor)
 	init_waitqueue_head(&file->event_wait);
 	file->event_space = 4096; /* set aside 4k for event buffer */
 
+	spin_lock_init(&file->master_lookup_lock);
 	mutex_init(&file->event_read_lock);
 
 	if (drm_core_check_feature(dev, DRIVER_GEM))
diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c
index da4f085fc09e7af1df311269decb2ea3a5802fa7..aef22634005ef869e49f6c048ac15bb1173a28e3 100644
--- a/drivers/gpu/drm/drm_lease.c
+++ b/drivers/gpu/drm/drm_lease.c
@@ -107,10 +107,19 @@ static bool _drm_has_leased(struct drm_master *master, int id)
  */
 bool _drm_lease_held(struct drm_file *file_priv, int id)
 {
-	if (!file_priv || !file_priv->master)
+	bool ret;
+	struct drm_master *master;
+
+	if (!file_priv)
 		return true;
 
-	return _drm_lease_held_master(file_priv->master, id);
+	master = drm_file_get_master(file_priv);
+	if (!master)
+		return true;
+	ret = _drm_lease_held_master(master, id);
+	drm_master_put(&master);
+
+	return ret;
 }
 
 /**
@@ -129,13 +138,22 @@ bool drm_lease_held(struct drm_file *file_priv, int id)
 	struct drm_master *master;
 	bool ret;
 
-	if (!file_priv || !file_priv->master || !file_priv->master->lessor)
+	if (!file_priv)
 		return true;
 
-	master = file_priv->master;
+	master = drm_file_get_master(file_priv);
+	if (!master)
+		return true;
+	if (!master->lessor) {
+		ret = true;
+		goto out;
+	}
 	mutex_lock(&master->dev->mode_config.idr_mutex);
 	ret = _drm_lease_held_master(master, id);
 	mutex_unlock(&master->dev->mode_config.idr_mutex);
+
+out:
+	drm_master_put(&master);
 	return ret;
 }
 
@@ -155,10 +173,16 @@ uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in)
 	int count_in, count_out;
 	uint32_t crtcs_out = 0;
 
-	if (!file_priv || !file_priv->master || !file_priv->master->lessor)
+	if (!file_priv)
 		return crtcs_in;
 
-	master = file_priv->master;
+	master = drm_file_get_master(file_priv);
+	if (!master)
+		return crtcs_in;
+	if (!master->lessor) {
+		crtcs_out = crtcs_in;
+		goto out;
+	}
 	dev = master->dev;
 
 	count_in = count_out = 0;
@@ -177,6 +201,9 @@ uint32_t drm_lease_filter_crtcs(struct drm_file *file_priv, uint32_t crtcs_in)
 		count_in++;
 	}
 	mutex_unlock(&master->dev->mode_config.idr_mutex);
+
+out:
+	drm_master_put(&master);
 	return crtcs_out;
 }
 
@@ -490,7 +517,7 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 	size_t object_count;
 	int ret = 0;
 	struct idr leases;
-	struct drm_master *lessor = lessor_priv->master;
+	struct drm_master *lessor;
 	struct drm_master *lessee = NULL;
 	struct file *lessee_file = NULL;
 	struct file *lessor_file = lessor_priv->filp;
@@ -502,12 +529,6 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 		return -EOPNOTSUPP;
 
-	/* Do not allow sub-leases */
-	if (lessor->lessor) {
-		DRM_DEBUG_LEASE("recursive leasing not allowed\n");
-		return -EINVAL;
-	}
-
 	/* need some objects */
 	if (cl->object_count == 0) {
 		DRM_DEBUG_LEASE("no objects in lease\n");
@@ -519,12 +540,22 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 		return -EINVAL;
 	}
 
+	lessor = drm_file_get_master(lessor_priv);
+	/* Do not allow sub-leases */
+	if (lessor->lessor) {
+		DRM_DEBUG_LEASE("recursive leasing not allowed\n");
+		ret = -EINVAL;
+		goto out_lessor;
+	}
+
 	object_count = cl->object_count;
 
 	object_ids = memdup_user(u64_to_user_ptr(cl->object_ids),
 			array_size(object_count, sizeof(__u32)));
-	if (IS_ERR(object_ids))
-		return PTR_ERR(object_ids);
+	if (IS_ERR(object_ids)) {
+		ret = PTR_ERR(object_ids);
+		goto out_lessor;
+	}
 
 	idr_init(&leases);
 
@@ -535,14 +566,15 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 	if (ret) {
 		DRM_DEBUG_LEASE("lease object lookup failed: %i\n", ret);
 		idr_destroy(&leases);
-		return ret;
+		goto out_lessor;
 	}
 
 	/* Allocate a file descriptor for the lease */
 	fd = get_unused_fd_flags(cl->flags & (O_CLOEXEC | O_NONBLOCK));
 	if (fd < 0) {
 		idr_destroy(&leases);
-		return fd;
+		ret = fd;
+		goto out_lessor;
 	}
 
 	DRM_DEBUG_LEASE("Creating lease\n");
@@ -578,6 +610,7 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 	/* Hook up the fd */
 	fd_install(fd, lessee_file);
 
+	drm_master_put(&lessor);
 	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl succeeded\n");
 	return 0;
 
@@ -587,6 +620,8 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev,
 out_leases:
 	put_unused_fd(fd);
 
+out_lessor:
+	drm_master_put(&lessor);
 	DRM_DEBUG_LEASE("drm_mode_create_lease_ioctl failed: %d\n", ret);
 	return ret;
 }
@@ -609,7 +644,7 @@ int drm_mode_list_lessees_ioctl(struct drm_device *dev,
 	struct drm_mode_list_lessees *arg = data;
 	__u32 __user *lessee_ids = (__u32 __user *) (uintptr_t) (arg->lessees_ptr);
 	__u32 count_lessees = arg->count_lessees;
-	struct drm_master *lessor = lessor_priv->master, *lessee;
+	struct drm_master *lessor, *lessee;
 	int count;
 	int ret = 0;
 
@@ -620,6 +655,7 @@ int drm_mode_list_lessees_ioctl(struct drm_device *dev,
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 		return -EOPNOTSUPP;
 
+	lessor = drm_file_get_master(lessor_priv);
 	DRM_DEBUG_LEASE("List lessees for %d\n", lessor->lessee_id);
 
 	mutex_lock(&dev->mode_config.idr_mutex);
@@ -643,6 +679,7 @@ int drm_mode_list_lessees_ioctl(struct drm_device *dev,
 		arg->count_lessees = count;
 
 	mutex_unlock(&dev->mode_config.idr_mutex);
+	drm_master_put(&lessor);
 
 	return ret;
 }
@@ -662,7 +699,7 @@ int drm_mode_get_lease_ioctl(struct drm_device *dev,
 	struct drm_mode_get_lease *arg = data;
 	__u32 __user *object_ids = (__u32 __user *) (uintptr_t) (arg->objects_ptr);
 	__u32 count_objects = arg->count_objects;
-	struct drm_master *lessee = lessee_priv->master;
+	struct drm_master *lessee;
 	struct idr *object_idr;
 	int count;
 	void *entry;
@@ -676,6 +713,7 @@ int drm_mode_get_lease_ioctl(struct drm_device *dev,
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 		return -EOPNOTSUPP;
 
+	lessee = drm_file_get_master(lessee_priv);
 	DRM_DEBUG_LEASE("get lease for %d\n", lessee->lessee_id);
 
 	mutex_lock(&dev->mode_config.idr_mutex);
@@ -703,6 +741,7 @@ int drm_mode_get_lease_ioctl(struct drm_device *dev,
 		arg->count_objects = count;
 
 	mutex_unlock(&dev->mode_config.idr_mutex);
+	drm_master_put(&lessee);
 
 	return ret;
 }
@@ -721,7 +760,7 @@ int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
 				void *data, struct drm_file *lessor_priv)
 {
 	struct drm_mode_revoke_lease *arg = data;
-	struct drm_master *lessor = lessor_priv->master;
+	struct drm_master *lessor;
 	struct drm_master *lessee;
 	int ret = 0;
 
@@ -731,6 +770,7 @@ int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 		return -EOPNOTSUPP;
 
+	lessor = drm_file_get_master(lessor_priv);
 	mutex_lock(&dev->mode_config.idr_mutex);
 
 	lessee = _drm_find_lessee(lessor, arg->lessee_id);
@@ -751,6 +791,7 @@ int drm_mode_revoke_lease_ioctl(struct drm_device *dev,
 
 fail:
 	mutex_unlock(&dev->mode_config.idr_mutex);
+	drm_master_put(&lessor);
 
 	return ret;
 }
diff --git a/fs/quota/quota_tree.c b/fs/quota/quota_tree.c
index c5562c871c8beff8e12bb92dfa75b1066e3ff3fc..c459ac0cb2c71a4a978af381191212b61c94ebc7 100644
--- a/fs/quota/quota_tree.c
+++ b/fs/quota/quota_tree.c
@@ -488,6 +488,13 @@ static int remove_tree(struct qtree_mem_dqinfo *info, struct dquot *dquot,
 		goto out_buf;
 	}
 	newblk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
+	if (newblk < QT_TREEOFF || newblk >= info->dqi_blocks) {
+		quota_error(dquot->dq_sb, "Getting block too big (%u >= %u)",
+			    newblk, info->dqi_blocks);
+		ret = -EUCLEAN;
+		goto out_buf;
+	}
+
 	if (depth == info->dqi_qtree_depth - 1) {
 		ret = free_dqentry(info, dquot, newblk);
 		newblk = 0;
@@ -587,6 +594,13 @@ static loff_t find_tree_dqentry(struct qtree_mem_dqinfo *info,
 	blk = le32_to_cpu(ref[get_index(info, dquot->dq_id, depth)]);
 	if (!blk)	/* No reference? */
 		goto out_buf;
+	if (blk < QT_TREEOFF || blk >= info->dqi_blocks) {
+		quota_error(dquot->dq_sb, "Getting block too big (%u >= %u)",
+			    blk, info->dqi_blocks);
+		ret = -EUCLEAN;
+		goto out_buf;
+	}
+
 	if (depth < info->dqi_qtree_depth - 1)
 		ret = find_tree_dqentry(info, dquot, blk, depth+1);
 	else
diff --git a/include/drm/drm_auth.h b/include/drm/drm_auth.h
index 6bf8b2b789919870afe5a1194554a831b0127815..f99d3417f3042bbfab637ab8c20fe81957754f27 100644
--- a/include/drm/drm_auth.h
+++ b/include/drm/drm_auth.h
@@ -107,6 +107,7 @@ struct drm_master {
 };
 
 struct drm_master *drm_master_get(struct drm_master *master);
+struct drm_master *drm_file_get_master(struct drm_file *file_priv);
 void drm_master_put(struct drm_master **master);
 bool drm_is_current_master(struct drm_file *fpriv);
 
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 716990bace1048139e0c316e07d97d30a71e53f2..42d04607d091f8d9bcf73514a91eec9e98e26ae9 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -226,15 +226,27 @@ struct drm_file {
 	/**
 	 * @master:
 	 *
-	 * Master this node is currently associated with. Only relevant if
-	 * drm_is_primary_client() returns true. Note that this only
-	 * matches &drm_device.master if the master is the currently active one.
+	 * Master this node is currently associated with. Protected by struct
+	 * &drm_device.master_mutex, and serialized by @master_lookup_lock.
+	 *
+	 * Only relevant if drm_is_primary_client() returns true. Note that
+	 * this only matches &drm_device.master if the master is the currently
+	 * active one.
+	 *
+	 * When dereferencing this pointer, either hold struct
+	 * &drm_device.master_mutex for the duration of the pointer's use, or
+	 * use drm_file_get_master() if struct &drm_device.master_mutex is not
+	 * currently held and there is no other need to hold it. This prevents
+	 * @master from being freed during use.
 	 *
 	 * See also @authentication and @is_master and the :ref:`section on
 	 * primary nodes and authentication <drm_primary_node>`.
 	 */
 	struct drm_master *master;
 
+	/** @master_lock: Serializes @master. */
+	spinlock_t master_lookup_lock;
+
 	/** @pid: Process that opened this file. */
 	struct pid *pid;