From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934234AbcHNLzx (ORCPT ); Sun, 14 Aug 2016 07:55:53 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:52342 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933976AbcHNLaU (ORCPT ); Sun, 14 Aug 2016 07:30:20 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Wei Tang" , "Xiubo Li" , "Zhang Zhuoyu" , "Paolo Bonzini" Date: Sat, 13 Aug 2016 18:42:58 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 54/94] kvm: Fix irq route entries exceeding KVM_MAX_IRQ_ROUTES In-Reply-To: X-SA-Exim-Connect-IP: 92.40.249.202 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.82-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Xiubo Li commit caf1ff26e1aa178133df68ac3d40815fed2187d9 upstream. These days, we experienced one guest crash with 8 cores and 3 disks, with qemu error logs as bellow: qemu-system-x86_64: /build/qemu-2.0.0/kvm-all.c:984: kvm_irqchip_commit_routes: Assertion `ret == 0' failed. And then we found one patch(bdf026317d) in qemu tree, which said could fix this bug. Execute the following script will reproduce the BUG quickly: irq_affinity.sh ======================================================================== vda_irq_num=25 vdb_irq_num=27 while [ 1 ] do for irq in {1,2,4,8,10,20,40,80} do echo $irq > /proc/irq/$vda_irq_num/smp_affinity echo $irq > /proc/irq/$vdb_irq_num/smp_affinity dd if=/dev/vda of=/dev/zero bs=4K count=100 iflag=direct dd if=/dev/vdb of=/dev/zero bs=4K count=100 iflag=direct done done ======================================================================== The following qemu log is added in the qemu code and is displayed when this bug reproduced: kvm_irqchip_commit_routes: max gsi: 1008, nr_allocated_irq_routes: 1024, irq_routes->nr: 1024, gsi_count: 1024. That's to say when irq_routes->nr == 1024, there are 1024 routing entries, but in the kernel code when routes->nr >= 1024, will just return -EINVAL; The nr is the number of the routing entries which is in of [1 ~ KVM_MAX_IRQ_ROUTES], not the index in [0 ~ KVM_MAX_IRQ_ROUTES - 1]. This patch fix the BUG above. Signed-off-by: Xiubo Li Signed-off-by: Wei Tang Signed-off-by: Zhang Zhuoyu Signed-off-by: Paolo Bonzini [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- virt/kvm/assigned-dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/virt/kvm/assigned-dev.c +++ b/virt/kvm/assigned-dev.c @@ -826,7 +826,7 @@ long kvm_vm_ioctl_assigned_device(struct if (copy_from_user(&routing, argp, sizeof(routing))) goto out; r = -EINVAL; - if (routing.nr >= KVM_MAX_IRQ_ROUTES) + if (routing.nr > KVM_MAX_IRQ_ROUTES) goto out; if (routing.flags) goto out;