__lll_lock_wait_private ()
    at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:96
96	2:	movl	%edx, %eax
(gdb) thread apply all bt
Thread 1 (Thread 0x7f8b9e029700 (LWP 5904)):
#0  __lll_lock_wait_private ()
    at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:96
#1  0x00000031246ad2d4 in _L_lock_2197 () from /lib64/libc.so.6
#2  0x00000031246ad0e7 in __tz_convert (timer=0x31249b0ee8, use_localtime=1, 
    tp=0x7f8b9e027910) at tzset.c:619
#3  0x0000003e90c5552f in virLogMessage (
    category=0x3e90de9fea "file.util/command.c", priority=1, 
    funcname=0x3e90deac33 "virCommandHook", linenr=1962, flags=0, 
    fmt=<optimized out>) at util/logging.c:734
#4  0x0000003e90c45cce in virCommandHook (data=0x7f8b880c3280)
    at util/command.c:1962
#5  0x0000003e90c466cc in virExecWithHook (argv=0x7f8b88071920, 
    envp=0x7f8b880c08a0, keepfd=<optimized out>, retpid=<optimized out>, 
    infd=27, outfd=0x7f8b880c33e8, errfd=0x7f8b880c33ec, flags=4, 
    data=0x7f8b880c3280, pidfile=0x0, hook=0x3e90c45a10 <virCommandHook>)
    at util/command.c:527
#6  0x0000003e90c482cc in virCommandRunAsync (cmd=0x7f8b880c3280, pid=0x0)
    at util/command.c:2046
#7  0x0000003e90c48acc in virCommandRun (cmd=0x7f8b880c3280, exitstatus=0x0)
    at util/command.c:1841
#8  0x0000000000465d92 in qemuCapsExtractVersionInfo (

    qemu=0x7f8b880c0e90 "/usr/bin/qemu", arch=0x4f9db6 "i686", retversion=0x0, 
    retflags=0x7f8b9e028448) at qemu/qemu_capabilities.c:1297
#9  0x00000000004665ed in qemuCapsInitGuest (caps=0x7f8b880c1b10, 
    old_caps=0x7f8b8c000a70, hostmachine=<optimized out>, info=0x733440, hvm=1)
    at qemu/qemu_capabilities.c:592
#10 0x0000000000466e09 in qemuCapsInit (old_caps=0x7f8b8c000a70)
    at qemu/qemu_capabilities.c:846
#11 0x000000000044c8a0 in qemuCreateCapabilities (oldcaps=<optimized out>, 
    driver=0x7f8b940146b0) at qemu/qemu_driver.c:242
#12 0x000000000045fb86 in qemudGetCapabilities (conn=<optimized out>)
    at qemu/qemu_driver.c:1004
#13 0x0000003e90cc835e in virConnectGetCapabilities (conn=0x7f8b84000b60)
    at libvirt.c:5877
#14 0x0000000000434ea3 in remoteDispatchGetCapabilities (ret=0x7f8b880adbf0, 
    rerr=0x7f8b9e028c70, hdr=<optimized out>, client=0x1834970, 
    server=<optimized out>) at remote_dispatch.h:5555
#15 remoteDispatchGetCapabilitiesHelper (server=<optimized out>, 
    client=0x1834970, hdr=<optimized out>, rerr=0x7f8b9e028c70, 
    args=<optimized out>, ret=0x7f8b880adbf0) at remote_dispatch.h:5536
#16 0x000000000043f42e in virNetServerProgramDispatchCall (msg=0x1877430, 
    client=0x1834970, server=0x182c410, prog=0x182c3e0)
    at rpc/virnetserverprogram.c:401
#17 virNetServerProgramDispatch (prog=0x182c3e0, server=0x182c410, 

#18 0x000000000044169c in virNetServerHandleJob (jobOpaque=<optimized out>, 
    opaque=0x182c410) at rpc/virnetserver.c:136
#19 0x0000003e90c65eae in virThreadPoolWorker (opaque=<optimized out>)
    at util/threadpool.c:144
#20 0x0000003e90c65962 in virThreadHelper (data=<optimized out>)
    at util/threads-pthread.c:157
#21 0x0000003124a07d90 in start_thread (arg=0x7f8b9e029700)
    at pthread_create.c:309
#22 0x00000031246eed8d in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:115