Description of problem:

Core dump when quitting

Version-Release number of selected component (if applicable):

kernel-2.6.32-358.6.1.el6.x86_64
qemu-kvm-0.12.1.2-2.355.el6_4.3.x86_64

How reproducible:
1/1

Steps to Reproduce:
1. CML:
 /root/autotest/autotest-devel/client/tests/kvm/qemu
     -S
     -name 'vm1'
     -nodefaults
     -chardev socket,id=qmp_id_qmpmonitor1,path=/tmp/monitor-qmpmonitor1-20130417-023721-qLPVffAl,server,nowait
     -mon chardev=qmp_id_qmpmonitor1,mode=control
     -chardev socket,id=serial_id_serial1,path=/tmp/serial-serial1-20130417-023721-qLPVffAl,server,nowait
     -device isa-serial,chardev=serial_id_serial1
     -chardev socket,id=seabioslog_id_20130417-023721-qLPVffAl,path=/tmp/seabios-20130417-023721-qLPVffAl,server,nowait
     -device isa-debugcon,chardev=seabioslog_id_20130417-023721-qLPVffAl,iobase=0x402
     -device ich9-usb-uhci1,id=usb1,bus=pci.0,addr=0x4
     -drive file='/root/autotest/autotest-devel/client/tests/kvm/images/win2008r2-64-virtio.qcow2',if=none,id=drive-virtio-disk1,media=disk,cache=none,boot=off,snapshot=off,format=qcow2,aio=native
     -device virtio-blk-pci,bus=pci.0,addr=0x5,drive=drive-virtio-disk1,id=virtio-disk1
     -device virtio-net-pci,netdev=idrBVLWX,mac=9a:88:89:8a:8b:8c,bus=pci.0,addr=0x3,id='idSDN2f3'
     -netdev tap,id=idrBVLWX,vhost=on,fd=22
     -m 32768
     -smp 16,maxcpus=16,cores=4,threads=2,sockets=2
     -cpu 'Opteron_G4',hv_relaxed
     -M rhel6.4.0
     -drive file='/root/autotest/autotest-devel/client/tests/kvm/isos/windows/winutils.iso',if=none,id=drive-ide0-0-0,media=cdrom,snapshot=off,format=raw
     -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0
     -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1
     -vnc :1
     -vga std
     -rtc base=localtime,clock=host,driftfix=slew
     -boot order=cdn,once=c,menu=off
     -enable-kvm

2.
3.
  
Actual results:

core dump

Expected results:

qemu works well & no core dump happen

Additional info:

1. 
(gdb) bt
#0  qemu_bh_delete (bh=0x643122203a226469) at /usr/src/debug/qemu-kvm-0.12.1.2/async.c:118
#1  0x00007f6f1cf62dbf in virtio_blk_dma_restart_bh (opaque=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/hw/virtio-blk.c:465
#2  0x00007f6f1cf85031 in qemu_bh_poll () at /usr/src/debug/qemu-kvm-0.12.1.2/async.c:70
#3  0x00007f6f1cf4e419 in main_loop_wait (timeout=1000) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4017
#4  0x00007f6f1cf7098a in kvm_main_loop () at /usr/src/debug/qemu-kvm-0.12.1.2/qemu-kvm.c:2244
#5  0x00007f6f1cf51018 in main_loop (argc=50, argv=<value optimized out>, envp=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:4187
#6  main (argc=50, argv=<value optimized out>, envp=<value optimized out>) at /usr/src/debug/qemu-kvm-0.12.1.2/vl.c:6526
(gdb) 

2. CpuInfo
processor	: 31
vendor_id	: AuthenticAMD
cpu family	: 21
model		: 1
model name	: AMD Opteron(TM) Processor 6272                 
stepping	: 2
cpu MHz		: 2100.129
cache size	: 2048 KB
physical id	: 1
siblings	: 16
core id		: 7
cpu cores	: 8
apicid		: 79
initial apicid	: 47
fpu		: yes
fpu_exception	: yes
cpuid level	: 13
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nonstop_tsc extd_apicid amd_dcm aperfmperf pni pclmulqdq monitor ssse3 cx16 sse4_1 sse4_2 popcnt aes xsave avx lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs xop skinit wdt lwp fma4 nodeid_msr topoext perfctr_core cpb npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold
bogomips	: 4199.76
TLB size	: 1536 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 48 bits physical, 48 bits virtual
power management: ts ttp tm 100mhzsteps hwpstate cpb