diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index d060fce4940ed7a4989ad1ec9dc8e432a1b3c316..28e3760e8b981ed20d1f46453c8405dbfc31bd42 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -616,7 +616,7 @@ static void console_write(struct console *console, const char *string,
 		return;
 
 	while(1){
-		n = min(len, ARRAY_SIZE(console_buf) - console_index);
+		n = min((size_t)len, ARRAY_SIZE(console_buf) - console_index);
 		strncpy(&console_buf[console_index], string, n);
 		console_index += n;
 		string += n;