diff --git a/arch/x86/kernel/genapic_64.c b/arch/x86/kernel/genapic_64.c
index 021624c835832d81f00f1ed6ef5d5437e9303813..cbaaf69bedb29c92055e2272a12efba7f49f9ee1 100644
--- a/arch/x86/kernel/genapic_64.c
+++ b/arch/x86/kernel/genapic_64.c
@@ -83,7 +83,7 @@ unsigned int read_apic_id(void)
 {
 	unsigned int id;
 
-	WARN_ON(preemptible());
+	WARN_ON(preemptible() && num_online_cpus() > 1);
 	id = apic_read(APIC_ID);
 	if (uv_system_type >= UV_X2APIC)
 		id  |= __get_cpu_var(x2apic_extra_bits);