diff --git a/[refs] b/[refs]
index 3d27a1849c99..684e84dc1cde 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 575ca7351bf0546919060071797cccb4a05960df
+refs/heads/master: f6c133f7d5ee3b82f5b34b988e897ea38cd8219c
diff --git a/trunk/arch/x86/kernel/genapic_64.c b/trunk/arch/x86/kernel/genapic_64.c
index 021624c83583..cbaaf69bedb2 100644
--- a/trunk/arch/x86/kernel/genapic_64.c
+++ b/trunk/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);