In Ubuntu Otto Berger reported: after updating from karmic to lucid, starting a virtual machine with a serial port throws an error and failed to start. if i remove the serial port (/dev/ttyS14) the machine start successfully... log entry: LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.11 -enable-kvm -m 2048 -smp 1,sockets=1,cores=1,threads=1 -name web2 -uuid 17c99639-2299-ce13-c1b6-c7a627dd181e -nodefaults -chardev socket,id=monitor,path=/var/lib/libvirt/qemu/web2.monitor,server,nowait -mon chardev=monitor,mode=readline -rtc base=utc -boot c -drive file=/dev/vmdata/web2,if=none,id=drive-virtio-disk0,boot=on -device virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0 -device virtio-net-pci,vlan=0,id=net0,mac=52:54:00:68:45:ab,bus=pci.0,addr=0x5 -net tap,fd=39,vlan=0,name=hostnet0 -chardev tty,id=serial0,path=/dev/ttyS14 -device isa-serial,chardev=serial0 -usb -vnc 127.0.0.1:0 -k de -vga cirrus -device ES1370,id=sound0,bus=pci.0,addr=0x6 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 chardev: opening backend "tty" failed You can see logs and configs in Launchpad ref: https://bugs.edge.launchpad.net/libvirt/+bug/578527 Thanks!
So, this turned out to be an AppArmor issue. I'll be updating the example profile and submit a patch to the mailing list during my next iteration.
Confirm bug in Fedora 13 If I remove all serial and parallel ports on virtual machine, I runs fine. once started and stopped, add serial port again and problem is over Tested with Windows XP SP3 as guest system
This bug is fixed in http://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=2e5e614e6b3b7407fe8741ab1a44ac323c0262e4 and present in fedora's libvirt now. So comment 2 is most likely about bug 596553
Closing per Comment #3