Since ftrace failed me I switched to gdb via the qemu -s parameter. Debuginfo and source of guest kernel on the Host: sudo apt-get install linux-tools-4.4.0-18-dbgsym sudo pull-lp-source linux 4.4.0-18.34 sudo mkdir -p /build/linux-XwpX40; sudo ln -s /home/ubuntu/linux-4.4.0 /build/linux-XwpX40/linux-4.4.0
Edit that into the guest and restart: <domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'> <qemu:commandline> <qemu:arg value='-s'/> </qemu:commandline> gdb /usr/lib/debug/boot/vmlinux-4.4.0-18-generic b dev_ethtool b ethtool_set_channels b virtnet_set_channels b virtnet_set_queues Then on the guest run sudo /usr/bin/testpmd --pci-blacklist 0000:00:03.0 --socket-mem 2048 -- --interactive --total-num-mbufs=2048 Attach gdb with target remote :1234 Then on the guest trigger the bug sudo ethtool -L eth1 combined 3 It is really "hanging" on that virtnet_send_command called from there. As expected the loop never breaks. 1010 /* Spin for a response, the kick causes an ioport write, trapping 1011 * into the hypervisor, so the request should be handled immediately. 1012 */ 1013 while (!virtqueue_get_buf(vi->cvq, &tmp) && 1014 !virtqueue_is_broken(vi->cvq)) 1015 cpu_relax(); 1016 1017 return vi->ctrl_status == VIRTIO_NET_OK; (gdb) n 1014 !virtqueue_is_broken(vi->cvq)) (gdb) 1013 while (!virtqueue_get_buf(vi->cvq, &tmp) && (gdb) 1015 cpu_relax(); [...] Infinite loop. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1570195 Title: Net tools cause kernel soft lockup after DPDK touched VirtIO-pci devices To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dpdk/+bug/1570195/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
