Index: uspace/srv/audio/hound/hound.c
===================================================================
--- uspace/srv/audio/hound/hound.c	(revision 4a8d0dd1629a42ad3c6e78f6c3807e0c3a00b6b0)
+++ uspace/srv/audio/hound/hound.c	(revision dd74b5bc75b8545cb0c656b5e1f16ef29d14609d)
@@ -146,4 +146,5 @@
 static void hound_remove_source_internal(hound_t *hound, audio_source_t *source)
 {
+	assert(fibril_mutex_is_locked(&hound->list_guard));
 	log_verbose("Removing source '%s'.", source->name);
 	if (!list_empty(&source->connections))