From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755115AbbCFKgp (ORCPT ); Fri, 6 Mar 2015 05:36:45 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:44348 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753965AbbCFJ70 (ORCPT ); Fri, 6 Mar 2015 04:59:26 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: David Hildenbrand , Christian Borntraeger , Luis Henriques Subject: [PATCH 3.16.y-ckt 087/183] KVM: s390: floating irqs: fix user triggerable endless loop Date: Fri, 6 Mar 2015 09:56:18 +0000 Message-Id: <1425635874-19087-88-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1425635874-19087-1-git-send-email-luis.henriques@canonical.com> References: <1425635874-19087-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt8 -stable review patch. If anyone has any objections, please let me know. ------------------ From: David Hildenbrand 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: Luis Henriques --- 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 e2354f97264e..f19702fc89ec 100644 --- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -925,6 +925,8 @@ 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 {