I have two stuck kvm guests hanging in state R (for several hours now) on two different hosts. Actually they are not consuming any CPU and cannot be killed with kill -9. They are not responding to anything. Both systems are Ubuntu 12.10 Quantal running on a AMD II X4 965 Processor with 16GB RAM.


Stack trace of the first stuck guest:

cat /proc/2647/stack 
[<ffffffff81683e06>] retint_careful+0x14/0x32
[<ffffffffffffffff>] 0xffffffffffffffff


Stack trace of the second stuck guest:

cat /proc/11932/stack
[<ffffffff81084d2a>] __cond_resched+0x2a/0x40
[<ffffffff811544aa>] try_to_unmap_file+0x3a/0x6d0
[<ffffffff811553c1>] try_to_unmap+0x31/0x70
[<ffffffff811722a8>] migrate_pages+0x318/0x500
[<ffffffff811453b4>] compact_zone+0x1e4/0x350
[<ffffffff811458bf>] try_to_compact_pages+0x16f/0x1d0
[<ffffffff81677a94>] __alloc_pages_direct_compact+0xaa/0x191
[<ffffffff8112bee3>] __alloc_pages_nodemask+0x473/0x920
[<ffffffff81164b30>] alloc_pages_current+0xb0/0x120
[<ffffffff8116bf5d>] new_slab+0x22d/0x2c0
[<ffffffff816790ea>] __slab_alloc+0x314/0x46e
[<ffffffff811708a1>] __kmalloc_node_track_caller+0xa1/0x1b0
[<ffffffff81566e99>] __alloc_skb+0x79/0x230
[<ffffffff81560a31>] sock_alloc_send_pskb+0x1d1/0x320
[<ffffffff81499ec1>] tun_get_user+0x131/0x4a0
[<ffffffff8149a759>] tun_chr_aio_write+0x69/0x90
[<ffffffff8118297a>] do_sync_readv_writev+0xda/0x120
[<ffffffff81182c64>] do_readv_writev+0xd4/0x1e0
[<ffffffff81182da5>] vfs_writev+0x35/0x60
[<ffffffff81182f2a>] sys_writev+0x4a/0xb0
[<ffffffff8168bb69>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff

Packages:

Kernel: 3.5.0-23-generic #35-Ubuntu SMP Thu Jan 24 13:15:40 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
KVM: 1.2.0+noroms-0ubuntu2.12.10.2

Command line:

kvm -name vm-16762 -machine pc-1.2 -enable-kvm -cpu kvm64 -smp sockets=1,cores=2 -m 1024 -vga cirrus -drive id=drive1245,if=none,cache=writeback,aio=native,format=raw,media=disk,file=rbd:kvm1/vm-16762-disk-1 -device virtio-blk-pci,id=hdrive1245,addr=0x12,drive=drive1245 -netdev tap,id=netdev1243,ifname=tap1243,script=,downscript= -device virtio-net-pci,id=nic1243,addr=0x03,mac=02:48:6e:2b:4e:55,netdev=netdev1243 -chardev socket,id=qmp,path=/var/run/kvm/vm-16762/qmp,server,nowait -mon chardev=qmp,mode=control -monitor unix:/var/run/kvm/vm-16762/mon,server,nowait -vnc 10.0.0.60:21,password -usbdevice tablet -nodefaults -pidfile /var/run/kvm/vm-16762/pid -boot menu=on -k de -chroot /var/run/kvm/vm-16762 -runas kvm -daemonize