Description of problem:
run iofuzz(sub test of autotest) test with rhel4.9 guest,guest may kernel panic && qemu-kvm process irresponsive 

Version-Release number of selected component (if applicable):
qemu-kvm-0.12.1.2-2.158.el6.x86_64

How reproducible:
10/1

Steps to Reproduce:
1.run iofuzz test with rhel4.9 guest on rhel6 host. 
2.wait till guest panic.
3.
qemu-kvm -name 'vm1' -chardev socket,id=GEZ,server,nowait -mon chardev=qmp_monitor_id_qmpmonitor1,mode=control -chardev socket,id=serial_id_20110420-181700-5GEZ,path=GEZ,server,nowait -device isa-serial,chardev=serial_id_20110420-181700-5GEZ -drive file='RHEL-4.9-32.qcow2',index=0,if=none,id=drive-ide0-0-0,media=disk,cache=none,format=qcow2,aio=native -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -device rtl8139,netdev=idb7aThU,mac=9a:a7:f4:78:16:6d,id=ndev00idb7aThU,bus=pci.0,addr=0x3 -netdev tap,id=idb7aThU,ifname='t0-181700-5GEZ',script='switch',downscript='no' -m 2048 -smp 2,cores=1,threads=1,sockets=2 -cpu cpu64-rhel6,+sse2,+x2apic -vnc :0 -rtc base=utc,clock=host,driftfix=none -M rhel6.1.0 -boot order=cdn,once=c,menu=off -usbdevice tablet -no-kvm-pit-reinjection -enable-kvm

 

  
Actual results:
guest panic

Expected results:
guest work normally

Additional info:
kernel-2.6.32-130.el6.x86_64
8G RAM



bt info collected by "gdb -p qemu-pid"
(gdb) bt
#0  0x0000003a7cedf443 in select () at ../sysdeps/unix/syscall-template.S:82
#1  0x000000000040b9a0 in main_loop_wait (timeout=1000) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4423
#2  0x000000000042b52a in kvm_main_loop () at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-kvm.c:2164
#3  0x000000000040ef55 in main_loop (argc=<value optimized out>, argv=<value optimized out>, 
    envp=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4640
#4  main (argc=<value optimized out>, argv=<value optimized out>, envp=<value optimized out>)
    at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:6845

######## iofuzz test info from autotest
   KVM iofuzz test:
    1) Log into a guest
    2) Enumerate all IO port ranges through /proc/ioports
    3) On each port of the range:
        * Read it
        * Write 0 to it
        * Write a random value to a random port on a random order

########