--- linux-3.6.noarch/arch/x86/kernel/apic/ipi.c~ 2013-01-23 10:48:14.716069615 -0500 +++ linux-3.6.noarch/arch/x86/kernel/apic/ipi.c 2013-01-23 10:48:26.217046545 -0500 @@ -106,7 +106,7 @@ void default_send_IPI_mask_logical(const unsigned long mask = cpumask_bits(cpumask)[0]; unsigned long flags; - if (WARN_ONCE(!mask, "empty IPI mask")) + if (!mask) return; local_irq_save(flags);