Index: uspace/lib/usb/src/debug.c
===================================================================
--- uspace/lib/usb/src/debug.c	(revision a2be82467145f1e53467382f4bc45f5ea3c9b1f6)
+++ uspace/lib/usb/src/debug.c	(revision ef7f0435c682bb46110ceb829704ce4b37f48b51)
@@ -219,5 +219,4 @@
 
 	va_list args;
-	va_start(args, format);
 
 	/*
@@ -231,18 +230,24 @@
 
 	if (log_stream != NULL) {
+		va_start(args, format);
+
 		fprintf(log_stream, "[%s]%s: ", log_prefix, level_name);
 		vfprintf(log_stream, format, args);
 		fflush(log_stream);
+
+		va_end(args);
 	}
 
 	if (level <= log_level) {
+		va_start(args, format);
+
 		fprintf(screen_stream, "[%s]%s: ", log_prefix, level_name);
 		vfprintf(screen_stream, format, args);
 		fflush(screen_stream);
+
+		va_end(args);
 	}
 
 	fibril_mutex_unlock(&log_serializer);
-
-	va_end(args);
 }