Index: uspace/drv/ohci/endpoint_list.c
===================================================================
--- uspace/drv/ohci/endpoint_list.c	(revision 5a2c42bd0e02f21ac673b0897cc3c6cd7816158b)
+++ uspace/drv/ohci/endpoint_list.c	(revision e05d6c3de69a0c5bbef2bb7873e04df4ce3f4b05)
@@ -191,5 +191,6 @@
 	assert(hcd_ep);
 	assert(hcd_ep->ed);
-	assert(fibril_mutex_is_locked(&instance->guard));
+
+	fibril_mutex_lock(&instance->guard);
 
 	usb_log_debug2(
@@ -218,4 +219,5 @@
 	/* Remove from the endpoint list */
 	list_remove(&hcd_ep->link);
+	fibril_mutex_unlock(&instance->guard);
 }
 /**