Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752251AbbD3MT1 (ORCPT ); Thu, 30 Apr 2015 08:19:27 -0400 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:53666 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751430AbbD3MMe (ORCPT ); Thu, 30 Apr 2015 08:12:34 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Marc Zyngier , Shannon Zhao , Jiri Slaby Subject: [PATCH 3.12 47/63] KVM: ARM: vgic: plug irq injection race Date: Thu, 30 Apr 2015 14:12:16 +0200 Message-Id: <64b4f742f29eb19cd8c669703de4102a67228076.1430387326.git.jslaby@suse.cz> X-Mailer: git-send-email 2.3.5 In-Reply-To: <45aaf85687dd6ac119c55c5ec0dbe0bef0e62235.1430387326.git.jslaby@suse.cz> References: <45aaf85687dd6ac119c55c5ec0dbe0bef0e62235.1430387326.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1728 Lines: 49 From: Marc Zyngier 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 71afaba4a2e98bb7bdeba5078370ab43d46e67a1 upstream. As it stands, nothing prevents userspace from injecting an interrupt before the guest's GIC is actually initialized. This goes unnoticed so far (as everything is pretty much statically allocated), but ends up exploding in a spectacular way once we switch to a more dynamic allocation (the GIC data structure isn't there yet). The fix is to test for the "ready" flag in the VGIC distributor before trying to inject the interrupt. Note that in order to avoid breaking userspace, we have to ignore what is essentially an error. Signed-off-by: Marc Zyngier Acked-by: Christoffer Dall Signed-off-by: Shannon Zhao Signed-off-by: Jiri Slaby --- virt/kvm/arm/vgic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index 91b5a9f96041..865a89178c82 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -1226,7 +1226,8 @@ out: int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num, bool level) { - if (vgic_update_irq_state(kvm, cpuid, irq_num, level)) + if (likely(vgic_initialized(kvm)) && + vgic_update_irq_state(kvm, cpuid, irq_num, level)) vgic_kick_vcpus(kvm); return 0; -- 2.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/