diff --git a/sbin/mount/mount_libmount.c b/sbin/mount/mount_libmount.c
index 3ec30f8..4040cd0 100644
--- a/sbin/mount/mount_libmount.c
+++ b/sbin/mount/mount_libmount.c
@@ -125,9 +125,7 @@ static void nilfs_mount_logger(int priority, const char *fmt, ...)
 	if ((verbose && priority > LOG_INFO) || priority >= LOG_INFO)
 		return;
 	va_start(args, fmt);
-	fprintf(stderr, "%s: ", progname);
-	vfprintf(stderr, fmt, args);
-	fputs(_("\n"), stderr);
+	vwarnx(fmt, args);
 	va_end(args);
 }
 
diff --git a/sbin/mount/umount_libmount.c b/sbin/mount/umount_libmount.c
index e33efda..5fa35a7 100644
--- a/sbin/mount/umount_libmount.c
+++ b/sbin/mount/umount_libmount.c
@@ -105,9 +105,7 @@ static void nilfs_umount_logger(int priority, const char *fmt, ...)
 	if ((verbose && priority > LOG_INFO) || priority >= LOG_INFO)
 		return;
 	va_start(args, fmt);
-	fprintf(stderr, "%s: ", progname);
-	vfprintf(stderr, fmt, args);
-	fputs(_("\n"), stderr);
+	vwarnx(fmt, args);
 	va_end(args);
 }