From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: [bug 1.1] -M pc-1.0 + vhost = SIGSEGV Date: Sun, 01 Jul 2012 19:06:24 +0400 Message-ID: <4FF06770.905@msgid.tls.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit To: KVM list Return-path: Received: from isrv.corpit.ru ([86.62.121.231]:46479 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932123Ab2GAPG0 (ORCPT ); Sun, 1 Jul 2012 11:06:26 -0400 Sender: kvm-owner@vger.kernel.org List-ID: When running current git version of qemu-kvm with -M pc-1.0 and with vhost-net enabled, it crashes with SIGSEGV right when linux guest loads a virtio-net module. I haven't tried to debug this deeply. The first result is: (gdb) ru -M pc-1.0 -nodefconfig -nodefaults -rtc base=utc -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -netdev tap,ifname=tap-kvm,script=no,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:b4:05:b5,bus=pci.0,addr=0x3 -vga cirrus Starting program: /build/kvm/debian/build/x86_64-softmmu/qemu-system-x86_64 -M pc-1.0 -nodefconfig -nodefaults -rtc base=utc -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -netdev tap,ifname=tap-kvm,script=no,id=hostnet0,vhost=on -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:b4:05:b5,bus=pci.0,addr=0x3 -vga cirrus ... Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 0xf65f4b70 (LWP 11245)] 0x5668b01a in virtio_pci_mask_vq (vector=vector@entry=1, vq=0x57064448, masked=masked@entry=0, dev=) at /build/kvm/debian/hw/virtio-pci.c:546 546 int r = kvm_set_irqfd(dev->msix_irq_entries[vector].gsi, Now, my gdb can't read `dev' variable. One level up the stack this variable is shown correctly: #1 0x5668b15d in virtio_pci_mask_notifier (dev=0x57062748, vector=1, masked=0) at /build/kvm/debian/hw/virtio-pci.c:576 576 r = virtio_pci_mask_vq(dev, vector, virtio_get_queue(vdev, n), masked); (gdb) p dev->msix_irq_entries[vector].gsi Cannot access memory at address 0x10 (gdb) p dev $1 = (PCIDevice *) 0x57062748 (gdb) p dev->msix_irq_entries $4 = (KVMMsiMessage *) 0x0 So it looks like msix isn't initialized for -M pc-1.0 ? Thanks, /mjt