Index: uspace/srv/devman/devman.c
===================================================================
--- uspace/srv/devman/devman.c	(revision 6e50466ff28e9edcba1f6e48348d531d12cd5e38)
+++ uspace/srv/devman/devman.c	(revision 8240dc5a6bfbb4e3c8ad048993eac2db271476f1)
@@ -384,4 +384,5 @@
 	printf(NAME ": create_root_node\n");
 
+	fibril_rwlock_write_lock(&tree->rwlock);
 	node = create_dev_node();
 	if (node != NULL) {
@@ -393,4 +394,5 @@
 		tree->root_node = node;
 	}
+	fibril_rwlock_write_unlock(&tree->rwlock);
 
 	return node != NULL;
@@ -455,6 +457,4 @@
 /** Start a driver
  *
- * The driver's mutex is assumed to be locked.
- *
  * @param drv		The driver's structure.
  * @return		True if the driver's task is successfully spawned, false
@@ -465,4 +465,6 @@
 	int rc;
 
+	assert(fibril_mutex_is_locked(&drv->driver_mutex));
+	
 	printf(NAME ": start_driver '%s'\n", drv->name);
 	
@@ -859,6 +861,4 @@
 /** Find the device node structure of the device witch has the specified handle.
  *
- * Device tree's rwlock should be held at least for reading.
- *
  * @param tree		The device tree where we look for the device node.
  * @param handle	The handle of the device.
@@ -868,5 +868,9 @@
 {
 	unsigned long key = handle;
-	link_t *link = hash_table_find(&tree->devman_devices, &key);
+	link_t *link;
+	
+	assert(fibril_rwlock_is_locked(&tree->rwlock));
+	
+	link = hash_table_find(&tree->devman_devices, &key);
 	return hash_table_get_instance(link, node_t, devman_link);
 }
@@ -924,7 +928,4 @@
 /** Insert new device into device tree.
  *
- * The device tree's rwlock should be already held exclusively when calling this
- * function.
- *
  * @param tree		The device tree.
  * @param node		The newly added device node. 
@@ -941,4 +942,5 @@
 	assert(tree != NULL);
 	assert(dev_name != NULL);
+	assert(fibril_rwlock_is_write_locked(&tree->rwlock));
 	
 	node->name = dev_name;