Re: [bug 1.1] -M pc-1.0 + vhost = SIGSEGV
On 2012-07-01 17:06, Michael Tokarev wrote: When running current git version of qemu-kvm with -M pc-1.0 Just to clarify: you are talking about stable-1.1 git, not master. 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=error reading variable: Unhandled dwarf expression opcode 0xfa) 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 ? Yes, because the machine option defaults are missing here. Will send a patch. Also vhost is buggy as it depends on in-kernel irqchip but doesn't check for it. Needs to be fixed as well. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [bug 1.1] -M pc-1.0 + vhost = SIGSEGV
02.07.2012 11:20, Jan Kiszka wrote: On 2012-07-01 17:06, Michael Tokarev wrote: When running current git version of qemu-kvm with -M pc-1.0 Just to clarify: you are talking about stable-1.1 git, not master. Yes, as the $Subject (partially) says. [] So it looks like msix isn't initialized for -M pc-1.0 ? And for earlier pc numbers too (eg -M pc-0.15). Yes, because the machine option defaults are missing here. Will send a patch. Also vhost is buggy as it depends on in-kernel irqchip but doesn't check for it. Needs to be fixed as well. And while we're at it, can we please take a look at the kernel side of this bug, mentioned in other my email? Namely, when qemu-kvm sigsegvs in this place, the (persistent) tap device becomes unusable and needs to be re-created (no packets are flowing). We've a nice reproducer now for this kernel issue. (Cc'ing mst for this) Thanks, /mjt -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
[bug 1.1] -M pc-1.0 + vhost = SIGSEGV
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=error reading variable: Unhandled dwarf expression opcode 0xfa) 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 -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [bug 1.1] -M pc-1.0 + vhost = SIGSEGV
On 01.07.2012 19:06, Michael Tokarev wrote: 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. And when this happens when a persistent tap device is used, that tap device becomes unusable until removed and recreated -- it works but no network packet goes on. So it looks like we've two bugs, one in userspace qemu 1.1 and another in host kernel (3.0). Thanks, /mjt -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
