From 6d6cdcaf12560db583b098baca23e3bdab78bcaa Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 15 Jan 2015 17:56:18 +0100 Subject: [PATCH] KVM: s390: floating irqs: fix user triggerable endless loop commit 8e2207cdd087ebb031e9118d1fd0902c6533a5e5 upstream. If a vm with no VCPUs is created, the injection of a floating irq leads to an endless loop in the kernel. Let's skip the search for a destination VCPU for a floating irq if no VCPUs were created. Reviewed-by: Dominik Dingel Reviewed-by: Cornelia Huck Signed-off-by: David Hildenbrand Signed-off-by: Christian Borntraeger Signed-off-by: Greg Kroah-Hartman --- arch/s390/kvm/interrupt.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c index b73b5db1ab42a..57ed057cba65f 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -850,6 +850,8 @@ static int __inject_vm(struct kvm *kvm, struct kvm_s390_interrupt_info *inti) list_add_tail(&inti->list, &iter->list); } atomic_set(&fi->active, 1); + if (atomic_read(&kvm->online_vcpus) == 0) + goto unlock_fi; sigcpu = find_first_bit(fi->idle_mask, KVM_MAX_VCPUS); if (sigcpu == KVM_MAX_VCPUS) { do { -- 2.47.3