Description of problem:
Bridge environment use openvswitch qemu-ifdown script under the etc directory,launch guest with error image, can't boot and qemu core dumped.


Version-Release number of selected component (if applicable):
3.10.0-382.el7.x86_64
qemu-kvm-rhev-2.5.0-4.el7.x86_64
How reproducible:
100%

Steps to Reproduce:
1.Host bridge environment,use openvswitch qemu-ifdown script under the etc directory, launch guest with error image,can't boot and qemu core dumped.
2.
3.

Actual results:
2016-04-20T09:12:58.562068Z qemu-kvm: -drive id=drive_image1,if=none,cache=none,snapshot=off,format=qcow2,file=/home/RHEL-Server-6.8-64-virtio.qcow1: Could not open '/home/RHEL-Server-6.8-64-virtio.qcow1': No such file or directory
ovs-vsctl: no port named tap0
2016-04-20T09:12:58.569239Z qemu-kvm:Segmentation fault (core dumped)

Expected results:
qemu quit and no core dumped.

Additional info:
/usr/libexec/qemu-kvm -name test \
-machine pc  \
-drive id=drive_image1,if=none,cache=none,snapshot=off,format=qcow2,file=/home/RHEL-Server-6.8-64-virtio.qcow1 \
-device virtio-blk-pci,id=image1,drive=drive_image1,bus=pci.0,bootindex=0 \
-netdev tap,id=hostnet0,vhost=off,queues=4 \
-device virtio-net-pci,netdev=hostnet0,mac=52:56:25:93:79:67,id=net0,status=on,vectors=10,mq=on\
-m 4096 \
-smp 4 \
-cpu SandyBridge \
-boot menu=on -enable-kvm \
-qmp tcp:0:5556,nowait,server \
-monitor stdio \
-spice port=5901,disable-ticketing  \
-vga qxl \
-msg timestamp=on \
-rtc base=utc

gdb info:
(gdb) bt full
#0  0x00007ffff00a0ab4 in vfprintf () from /lib64/libc.so.6
No symbol table info available.
#1  0x00007ffff00a4801 in buffered_vfprintf () from /lib64/libc.so.6
No symbol table info available.
#2  0x00007ffff009f73e in vfprintf () from /lib64/libc.so.6
No symbol table info available.
#3  0x00007ffff016392d in __vfprintf_chk () from /lib64/libc.so.6
No symbol table info available.
#4  0x0000555555959a19 in error_printf (fmt=fmt@entry=0x5555559a3c7a "%s%s") at util/qemu-error.c:40
        ap = {{gp_offset = 24, fp_offset = 48, overflow_arg_area = 0x7fffffffbb20, reg_save_area = 0x7fffffffba60}}
#5  0x0000555555959ea0 in error_print_loc () at util/qemu-error.c:183
        sep = <optimized out>
        i = 0
        argp = <optimized out>
#6  error_vreport (fmt=0x5555559df758 "%s", ap=ap@entry=0x7fffffffbb70) at util/qemu-error.c:220
        tv = {tv_sec = 1461142674, tv_usec = 296119}
        timestr = <optimized out>
#7  0x0000555555959f69 in error_report (fmt=fmt@entry=0x5555559df758 "%s") at util/qemu-error.c:237
        ap = {{gp_offset = 8, fp_offset = 48, overflow_arg_area = 0x7fffffffbc50, reg_save_area = 0x7fffffffbb90}}
#8  0x0000555555959475 in error_report_err (err=0x555556ac6ff0) at util/error.c:205
No locals.
#9  0x000055555589d68a in tap_cleanup (nc=0x555556bd6000) at net/tap.c:309
        err = 0x555556ac6ff0
#10 0x0000555555898195 in qemu_del_net_client (nc=0x555556bd6000) at net/net.c:429
        ncs = {0x555556bd6000, 0x555556be8000, 0x555556bfa000, 0x555556c0c000, 0x0 <repeats 15 times>, 
          0x7fffebdf5135 <_UIx86_64__mempool_alloc+133>, 0xfffffffe7ffbfeff, 0x0 <repeats 16 times>, 0x9a267f9f81baa400, 0x7fffffffca10, 
          0x7fffec002220, 0x555555a4cb08, 0x7fffebdf8717 <_ULx86_64_dwarf_extract_proc_info_from_fde+919>, 0x7fffffffca10, 0x0, 0x7fffec002220, 
          0x100000000, 0x7fffffffbe58, 0x7fffffffbe18, 0x5555556b8860 <main>, 0x1000050f6, 0x555555a4cac9, 0x555555a23481, 0x555555a23481, 
          0x555555a23488, 0x555555a4cac9, 0x555555a4cb08, 0x1, 0xfffffffffffffff8, 0x10, 0x9a267f9f81baa400, 0x1ff1b00000000, 0x7fffffffbec0, 
          0x75, 0x7ffff7ffd000 <_rtld_local>, 0x1, 0x0, 0x555556b31e00, 0x7ffff0188566 <dl_iterate_phdr+438>, 0x0, 0x555500000000, 
          0x7fffebdfa530 <_ULx86_64_dwarf_callback>, 0x7fffffffbfd0, 0x7fffe653f000, 0x555556b9e260, 0x7fffe653f040, 0x7fffffff0007, 0x75, 0x0, 
          0x0, 0x0, 0x5f04c, 0x7fffffffbfd0, 0xffffffffffffffff, 0x7fffebdf5135 <_UIx86_64__mempool_alloc+133>, 0xfffffffe7ffbfeff, 0xfffffff6, 
          0x7fffffffbf50, 0x7fffebdfab71 <_ULx86_64_dwarf_find_proc_info+177>, 0x7fffec002220, 0x7fffffffca10, 0xfffffffe7ffbfeff, 0x13, 
          0x100000004, 0x7fffebdf51fe <_UIx86_64__mempool_free+126>, 0xfffffffe7ffbfeff, 0x7ffff7fa14c8, 0x7fffffffc100, 
          0x7ffff7de5e99 <_dl_add_to_namespace_list+25>, 0x0, 0x37ffff1a0, 0x7fffffffc100, 0x9a267f9f81baa400, 0x7fffffffcc10, 0x7fffec002220, 
          0x555555a92710, 0x7fffebdf8717 <_ULx86_64_dwarf_extract_proc_info_from_fde+919>, 0x7fffffffcc10, 0x7fffffffcae8, 0x7fffec002220, 
---Type <return> to continue, or q <return> to quit---
          0x100000000, 0x7fffffffc058, 0x7fffffffc018, 0x55555590d960 <blk_new_open>, 0x100000111, 0x555555a926b9, 0x555555a23481, 
          0x555555a23481, 0x555555a23488, 0x555555a926b9, 0x555555a92710, 0x1, 0xfffffffffffffff8, 0x10, 0x9a267f9f81baa400, 0x1ff1b00000000, 
          0x7fffffffc0c0, 0x75, 0x7ffff7ffd000 <_rtld_local>, 0x1, 0x0, 0x555556b31e00, 0x7ffff0188566 <dl_iterate_phdr+438>, 0x0, 
          0x555500000000, 0x7fffebdfa530 <_ULx86_64_dwarf_callback>, 0x7fffffffc1d0, 0x7fffe653f000, 0x555556b9e260, 0x7fffe653f040, 
          0x7fffffff0007, 0x75, 0x0, 0x0, 0x0, 0x7ffff7fa14c8, 0x7fffffffc1d0, 0xffffffffffffffff, 0x7fffffffcce8, 0x1, 0xfffffff6, 
          0x7fffffffc150, 0x7fffebdfab71 <_ULx86_64_dwarf_find_proc_info+177>, 0x7fffec002220, 0x7fffffffcc10, 0xfffffffe7ffbfeff, 0x100000000, 
          0xc, 0x7fffebdf51fe <_UIx86_64__mempool_free+126>, 0xfffffffe7ffbfeff, 0x7ffff7f9e630, 0x7fffffffe030, 0x340, 0x0, 0x1, 0x0, 0x1, 0x0, 
          0x1, 0x0, 0x1, 0xffffffffffffffff, 0x7fffffffcce8, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0xffffffff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 
          0x0, 0xffffffff, 0x0, 0x0, 0x0, 0x0, 0x9a267f9f81baa400, 0x7fffffffcc10, 0x7fffffffcc10, 0xffffffffffffffff, 0x1, 0x7fffffffcce8, 
          0xfffffff6, 0x555556325000, 0x7fffebdf8b45 <fetch_proc_info+373>, 0x7fffec002278, 0x7fffec002220, 0x7fffffffcc10, 0x7fffec00ae78, 
          0x7fffffffc858, 0x7fffebdfa299 <_ULx86_64_dwarf_find_save_locs+1593>, 0x0, 0x1, 0x10002240...}
        queues = <optimized out>
        i = <optimized out>
        nf = <optimized out>
        next = <optimized out>
        __PRETTY_FUNCTION__ = "qemu_del_net_client"
#11 0x000055555589902d in net_cleanup () at net/net.c:1370
        nc = <optimized out>
#12 0x00007ffff0090e69 in __run_exit_handlers () from /lib64/libc.so.6
No symbol table info available.
#13 0x00007ffff0090eb5 in exit () from /lib64/libc.so.6
No symbol table info available.
#14 0x00005555556b9063 in main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at vl.c:4106
        i = <optimized out>
        snapshot = <optimized out>
        linux_boot = <optimized out>
        initrd_filename = <optimized out>
        kernel_filename = <optimized out>
        kernel_cmdline = <optimized out>
        boot_order = <optimized out>
        boot_once = <optimized out>
        cyls = <optimized out>
        heads = <optimized out>
        secs = <optimized out>
        translation = <optimized out>
        hda_opts = <optimized out>
---Type <return> to continue, or q <return> to quit---
        opts = <optimized out>
        machine_opts = <optimized out>
        icount_opts = <optimized out>
        olist = <optimized out>
        optind = 34
        optarg = 0x555556ad24d8 "pc"
        loadvm = <optimized out>
        machine_class = <optimized out>
        cpu_model = <optimized out>
        vga_model = <optimized out>
        qtest_chrdev = <optimized out>
        qtest_log = <optimized out>
        pid_file = <optimized out>
        incoming = <optimized out>
        show_vnc_port = <optimized out>
        defconfig = <optimized out>
        userconfig = 203
        log_mask = <optimized out>
        log_file = <optimized out>
        trace_events = <optimized out>
        trace_file = <optimized out>
        maxram_size = <optimized out>
        ram_slots = <optimized out>
        vmstate_dump_file = <optimized out>
        main_loop_err = 0x0
        err = 0x0
        __func__ = "main"