The guest kernel hangs occasionally (1 time in 10 or less) during boot with the latest KVM and guest kernel from Rawhide. The last kernel messages before the hang are: Dentry cache hash table entries: 65536 (order: 7, 524288 bytes) Inode-cache hash table entries: 32768 (order: 6, 262144 bytes) Mount-cache hash table entries: 256 Initializing cgroup subsys ns Initializing cgroup subsys cpuacct Initializing cgroup subsys memory Initializing cgroup subsys devices Initializing cgroup subsys freezer Initializing cgroup subsys net_cls CPU: L1 I cache: 32K, L1 D cache: 32K CPU: L2 cache: 2048K CPU 0/0x0 -> Node 0 SMP alternatives: switching to UP code ACPI: Core revision 20081204 ftrace: converting mcount calls to 0f 1f 44 00 00 ftrace: allocating 18877 entries in 149 pages Setting APIC routing to flat ..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1 CPU0: Intel QEMU Virtual CPU version 0.10.0 stepping 03 The full KVM command line is: /usr/bin/qemu-kvm -drive file=test1.img -m 384 -no-reboot -kernel vmlinuz.rawhide.x86_64 -initrd initramfs.rawhide.x86_64.img -append 'panic=1 console=ttyS0 guestfs=10.0.2.4:6666 guestfs_verbose=1' -nographic -serial stdio -net channel,6666:unix:/tmp/libguestfsjm0kll/sock,server,nowait -net user,vlan=0 -net nic,model=virtio,vlan=0 KVM version: qemu-kvm-0.10.50-3.kvm85.fc12.x86_64 Guest kernel version: 2.6.29.2-126.fc11.x86_64 (mockbuild.phx.redhat.com) (gcc version 4.4.0 20090427 (Red Hat 4.4.0-3) (GCC) ) #1 SMP Mon May 4 04:46:15 EDT 2009 Host kernel: Linux intel-mb 2.6.29-0.258.2.3.rc8.git2.fc11.x86_64 #1 SMP Tue Mar 24 18:39:53 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux Various discussion leads us to believe that this might be caused by a mismatch between the qemu and KVM BIOS. FWIW the BIOS image that KVM is using is the one in /usr/share/qemu/bios.bin and /usr/share/qemu/vgabios.bin
Most likely that the KVM boch bios needs updating http://www.redhat.com/archives/fedora-virt/2009-May/msg00061.html
I should add that my original estimate ("1 time in 10 or less") is poor. It's more like 1 time in 100 in my test script (which just runs qemu-kvm in a loop). However it does occur more frequently in the libguestfs checks (more like 1 in 10). And during Koji builds, where I originally found the problem, it seems more like 1 in 2. I don't exactly know what the factor is that triggers this though.
(In reply to comment #1) > Most likely that the KVM boch bios needs updating > > http://www.redhat.com/archives/fedora-virt/2009-May/msg00061.html I seem to be using the latest bochs / bochs-bios: # rpm -qi bochs-bios Name : bochs-bios Relocations: (not relocatable) Version : 2.3.8 Vendor: Fedora Project Release : 0.6.git04387139e3b.fc11 Build Date: Wed 11 Mar 2009 05:26:02 PM GMT Install Date: Thu 26 Mar 2009 03:47:03 PM GMT Build Host: x86-2.fedora.phx.redhat.com Group : Applications/Emulators Source RPM: bochs-2.3.8-0.6.git04387139e3b.fc11.src.rpm Size : 327680 License: LGPLv2+ Signature : (none) Packager : Fedora Project URL : http://bochs.sourceforge.net/ Summary : Bochs bios Description : Bochs BIOS is a free implementation of a x86 BIOS provided by the Bochs projects. It can also be used in other emulators, such as QEMU That's the latest one I can find in Koji anyway (build here: http://koji.fedoraproject.org/koji/buildinfo?buildID=93823 ) Do we really still think this is a BIOS problem? May be a red herring.
I've retested this with: guest kernel 2.6.30-0.81.rc5.git1.fc12 qemu-kvm-0.10.50-4.kvm86.fc12 and for whatever reason the bug has gone away.