Index: funcs/func_volume.c
===================================================================
--- funcs/func_volume.c	(revision 367265)
+++ funcs/func_volume.c	(working copy)
@@ -90,6 +90,9 @@
 	struct volume_information *vi = data;
 
 	/* Destroy the audiohook, and destroy ourselves */
+	ast_audiohook_lock(&vi->audiohook);
+	ast_audiohook_detach(&vi->audiohook);
+	ast_audiohook_unlock(&vi->audiohook);
 	ast_audiohook_destroy(&vi->audiohook);
 	ast_free(vi);