3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Bonzini <pbonzini@xxxxxxxxxx> commit 5678de3f15010b9022ee45673f33bcfc71d47b60 upstream. QE reported that they got the BUG_ON in ioapic_service to trigger. I cannot reproduce it, but there are two reasons why this could happen. The less likely but also easiest one, is when kvm_irq_delivery_to_apic does not deliver to any APIC and returns -1. Because irqe.shorthand == 0, the kvm_for_each_vcpu loop in that function is never reached. However, you can target the similar loop in kvm_irq_delivery_to_apic_fast; just program a zero logical destination address into the IOAPIC, or an out-of-range physical destination address. Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- virt/kvm/ioapic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/virt/kvm/ioapic.c +++ b/virt/kvm/ioapic.c @@ -306,7 +306,7 @@ static int ioapic_deliver(struct kvm_ioa BUG_ON(ioapic->rtc_status.pending_eoi != 0); ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, ioapic->rtc_status.dest_map); - ioapic->rtc_status.pending_eoi = ret; + ioapic->rtc_status.pending_eoi = (ret < 0 ? 0 : ret); } else ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, NULL); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html