From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amos Kong Subject: [RFC] [PATCH v2] kvm tools: Make virt_queue__available return false if queue is not initialized. Date: Sun, 10 Apr 2011 16:33:39 +0800 Message-ID: <20110410083339.GC3253@t400> References: <1302411665-5349-1-git-send-email-asias.hejun@gmail.com> Reply-To: Amos Kong Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Asias He , Cyrill Gorcunov , Ingo Molnar , kvm@vger.kernel.org To: Pekka Enberg Return-path: Received: from mx1.redhat.com ([209.132.183.28]:10981 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753145Ab1DJIdv (ORCPT ); Sun, 10 Apr 2011 04:33:51 -0400 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: virtio_console__inject_interrupt tries to use virt queues before guest tell us to initialize them. (gdb) r run -i linux-0.2.img -k ./vmlinuz-2.6.38-rc6+ -r ./initrd.img-2.6.38-rc6+ -p=init=1 -m 500 -c Starting program: /project/rh/kvm-tools/tools/kvm/kvm run -i linux-0.2.img -k ./vmlinuz-2.6.38-rc6+ -r ./initrd.img-2.6.38-rc6+ -p=init=1 -m 500 -c [Thread debugging using libthread_db enabled] [New Thread 0x7fffd6e2d700 (LWP 19280)] Warning: request type 8 Program received signal SIGSEGV, Segmentation fault. 0x00000000004026ca in virt_queue__available (vq=0x60d3c8) at include/kvm/virtio.h:31 31 return vq->vring.avail->idx != vq->last_avail_idx; (gdb) (gdb) bt (gdb) p *vq $2 = {vring = {num = 0, desc = 0x0, avail = 0x0, used = 0x0}, pfn = 0, last_avail_idx = 0} include/kvm/virtio-console.h: 59 void virtio_console__inject_interrupt(struct kvm *self) .... 71 if (term_readable(CONSOLE_VIRTIO) && virt_queue__available(vq)) { 72 head = virt_queue__get_iov(vq, iov, &out, &in, self); ^^^^ then this block will not be executed if virtio_queue is unavaiable. Changes from v1: - move the check of virt_queue out of virt_queue__get_iov() Reported-by: Amos Kong Signed-off-by: Asias He Signed-off-by: Amos Kong --- tools/kvm/include/kvm/virtio.h | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/tools/kvm/include/kvm/virtio.h b/tools/kvm/include/kvm/virtio.h index 9f892a1..c8ff376 100644 --- a/tools/kvm/include/kvm/virtio.h +++ b/tools/kvm/include/kvm/virtio.h @@ -28,6 +28,8 @@ static inline struct vring_desc *virt_queue__get_desc(struct virt_queue *queue, static inline bool virt_queue__available(struct virt_queue *vq) { + if (!vq->vring.avail) + return 0; return vq->vring.avail->idx != vq->last_avail_idx; } -- 1.7.1