Created attachment 498679 [details]
guest-kernel-panic-serial.log

Description of problem:
Guest(rhel4.9-64) kernel panic during shutdown.

Version-Release number of selected component (if applicable):
kvm-83-232.el5
kernel 2.6.18-259.el5

How reproducible:
only once

Steps to Reproduce:
1. create a snapshot 
#qemu-img create -b RHEL-4.9-64.raw -f qcow2 sn1.qcow2

2. boot up new created sn1.qcow2 with cmd
******** cmd line ********
#/usr/libexec/qemu-kvm -drive file='sn1.qcow2',index=0,if=ide,media=disk,cache=none,format=qcow2 -net nic,vlan=0,model=e1000,macaddr='9a:ee:93:df:01:06' -net tap,vlan=0,ifname='t0-091953-J5dh',script='qemu-ifup-switch',downscript='no' -m 32768 -smp 8,cores=1,threads=1,sockets=8 -cpu qemu64,+sse2 -soundhw ac97 -spice port=8000,disable-ticketing -qxl 1 -rtc-td-hack -M rhel5.6.0 -boot c  -usbdevice tablet -no-kvm-pit-reinjection
**************************

3. create big file in guest
#dd if=/dev/zero of=/tmp/file_sn1 bs=1M count=1000

4. shutdown guest
#shutdown -h now
  
Actual results:
guest kernel panic

Expected results:
guest shutdown normally

Additional info:
Tested 20 times, hit this bug only once.