diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 1504eb8d25aa..004cb30b7419 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -360,7 +360,7 @@ static bool strict_sigaltstack_size __ro_after_init = false;
 
 static int __init strict_sas_size(char *arg)
 {
-	return kstrtobool(arg, &strict_sigaltstack_size);
+	return kstrtobool(arg, &strict_sigaltstack_size) == 0;
 }
 __setup("strict_sas_size", strict_sas_size);