diff --git a/kernel/cpu.c b/kernel/cpu.c
index 3225c3a9d028..985195bd03e4 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -851,6 +851,9 @@ static int __init mitigations_parse_cmdline(char *arg)
 		cpu_mitigations = CPU_MITIGATIONS_OFF;
 	else if (!strcmp(arg, "auto"))
 		cpu_mitigations = CPU_MITIGATIONS_AUTO;
+	else
+		pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n",
+			arg);
 
 	return 0;
 }