Index: uspace/srv/devman/devman.c
===================================================================
--- uspace/srv/devman/devman.c	(revision be942bcc856b2dbd86ad3891336fb7b52bb2b624)
+++ uspace/srv/devman/devman.c	(revision 01b87dc5664e19efa4e06cec91860b0ef1ece7da)
@@ -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;
Index: uspace/srv/devmap/devmap.c
===================================================================
--- uspace/srv/devmap/devmap.c	(revision be942bcc856b2dbd86ad3891336fb7b52bb2b624)
+++ uspace/srv/devmap/devmap.c	(revision 01b87dc5664e19efa4e06cec91860b0ef1ece7da)
@@ -46,4 +46,5 @@
 #include <str.h>
 #include <ipc/devmap.h>
+#include <assert.h>
 
 #define NAME          "devmap"
@@ -208,13 +209,11 @@
 }
 
-/** Find namespace with given name.
- *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
- */
+/** Find namespace with given name. */
 static devmap_namespace_t *devmap_namespace_find_name(const char *name)
 {
 	link_t *item;
+	
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+	
 	for (item = namespaces_list.next; item != &namespaces_list; item = item->next) {
 		devmap_namespace_t *namespace =
@@ -229,7 +228,4 @@
 /** Find namespace with given handle.
  *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
  * @todo: use hash table
  *
@@ -238,4 +234,7 @@
 {
 	link_t *item;
+	
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+	
 	for (item = namespaces_list.next; item != &namespaces_list; item = item->next) {
 		devmap_namespace_t *namespace =
@@ -248,14 +247,12 @@
 }
 
-/** Find device with given name.
- *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
- */
+/** Find device with given name. */
 static devmap_device_t *devmap_device_find_name(const char *ns_name,
     const char *name)
 {
 	link_t *item;
+	
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+	
 	for (item = devices_list.next; item != &devices_list; item = item->next) {
 		devmap_device_t *device =
@@ -271,7 +268,4 @@
 /** Find device with given handle.
  *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
  * @todo: use hash table
  *
@@ -280,4 +274,7 @@
 {
 	link_t *item;
+	
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+	
 	for (item = devices_list.next; item != &devices_list; item = item->next) {
 		devmap_device_t *device =
@@ -290,13 +287,12 @@
 }
 
-/** Create a namespace (if not already present)
- *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
- */
+/** Create a namespace (if not already present). */
 static devmap_namespace_t *devmap_namespace_create(const char *ns_name)
 {
-	devmap_namespace_t *namespace = devmap_namespace_find_name(ns_name);
+	devmap_namespace_t *namespace;
+	
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+	
+	namespace = devmap_namespace_find_name(ns_name);
 	if (namespace != NULL)
 		return namespace;
@@ -323,12 +319,9 @@
 }
 
-/** Destroy a namespace (if it is no longer needed)
- *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
- */
+/** Destroy a namespace (if it is no longer needed). */
 static void devmap_namespace_destroy(devmap_namespace_t *namespace)
 {
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+
 	if (namespace->refcnt == 0) {
 		list_remove(&(namespace->namespaces));
@@ -339,37 +332,28 @@
 }
 
-/** Increase namespace reference count by including device
- *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
- */
+/** Increase namespace reference count by including device. */
 static void devmap_namespace_addref(devmap_namespace_t *namespace,
     devmap_device_t *device)
 {
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+
 	device->namespace = namespace;
 	namespace->refcnt++;
 }
 
-/** Decrease namespace reference count
- *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
- */
+/** Decrease namespace reference count. */
 static void devmap_namespace_delref(devmap_namespace_t *namespace)
 {
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+
 	namespace->refcnt--;
 	devmap_namespace_destroy(namespace);
 }
 
-/** Unregister device and free it
- *
- * The devices_list_mutex should be already held when
- * calling this function.
- *
- */
+/** Unregister device and free it. */
 static void devmap_device_unregister_core(devmap_device_t *device)
 {
+	assert(fibril_mutex_is_locked(&devices_list_mutex));
+
 	devmap_namespace_delref(device->namespace);
 	list_remove(&(device->devices));