From 412aa73f2b041bb1341f6b154cd933bcbbe1c528 Mon Sep 17 00:00:00 2001 From: Amos Kong Date: Sun, 10 Apr 2011 16:33:39 +0800 Subject: [PATCH] kvm tools: Make virt_queue__available return false if queue is not initialized 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 Acked-by: Cyrill Gorcunov Signed-off-by: Asias He Signed-off-by: Amos Kong Signed-off-by: Pekka Enberg --- include/kvm/virtio.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/kvm/virtio.h b/include/kvm/virtio.h index 9f892a1..7903a74 100644 --- a/include/kvm/virtio.h +++ b/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; }