UID        PID  PPID  C STIME TTY          TIME CMD
qemu     17307 17305  0 13:24 ?        00:00:00 /opt/qemu-installed/bin/qemu-system-i386 -S -no-user-config -nodefaults -nographic -M none -qmp unix:/var/lib/libvirt/qemu/capabilities.monitor.sock,server,nowait -pidfile /var/lib/libvirt/qemu/capabilities.pidfile -daemonize

(gdb) thread apply all bt full

Thread 1 (Thread 0x7fa9ce6f2bc0 (LWP 17307)):
#0  0x00007fa9cd304f7d in __lll_lock_wait () from /lib64/libpthread.so.0
No symbol table info available.
#1  0x00007fa9cd300d32 in _L_lock_791 () from /lib64/libpthread.so.0
No symbol table info available.
#2  0x00007fa9cd300c38 in pthread_mutex_lock () from /lib64/libpthread.so.0
No symbol table info available.
#3  0x00007fa9cebc0ad1 in qemu_mutex_lock (mutex=0x7fa9cf524560 <rcu_sync_lock>) at util/qemu-thread-posix.c:73
        err = 0
        __func__ = "qemu_mutex_lock"
#4  0x00007fa9cebd491a in rcu_init_lock () at util/rcu.c:329
No locals.
#5  0x00007fa9c7da7512 in fork () from /lib64/libc.so.6
No symbol table info available.
#6  0x00007fa9ce915cef in os_daemonize () at os-posix.c:240
        pid = 0
        fds = {4, 5}
#7  0x00007fa9ce92a803 in main (argc=12, argv=0x7fff03f8efd8, envp=0x7fff03f8f040) at vl.c:4034
        i = 0
        snapshot = 0
        linux_boot = 0
        initrd_filename = 0x7fa9d0749eb0 "îkÅΩ\177"
        kernel_filename = 0x7fa9d0749ea0 ""
        kernel_cmdline = 0x7fa9cebd4e20 <__libc_csu_init> "AWA\211ÿAVI\211öAUI\211ÕATL\215%"
        boot_order = 0x0
        boot_once = 0x0
        ds = 0x7fa9cec56d38
        cyls = 0
        heads = 0
        secs = 0
        translation = 0
        hda_opts = 0x0
        opts = 0x7fa9d0790e90
        machine_opts = 0xfffffffe7fffffff
        icount_opts = 0x0
        olist = 0x7fa9cf03b140 <qemu_machine_opts>
        optind = 12
        optarg = 0x7fa9d0790f40 "none"
        loadvm = 0x0
        machine_class = 0x7fa9d077a160
        cpu_model = 0x0
        vga_model = 0x0
        qtest_chrdev = 0x0
        qtest_log = 0x0
        pid_file = 0x7fff03f8ff59 "/var/lib/libvirt/qemu/capabilities.pidfile"
        incoming = 0x0
        show_vnc_port = 0
        defconfig = true
        userconfig = false
        log_mask = 0x0
        log_file = 0x0
        mem_trace = {malloc = 0x7fa9ce9276a2 <malloc_and_trace>, realloc = 0x7fa9ce9276d7 <realloc_and_trace>, free = 0x7fa9ce92771b <free_and_trace>, calloc = 0x0, try_malloc = 0x0, try_realloc = 0x0}
        trace_events = 0x0
        trace_file = 0x0
        maxram_size = 134217728
        ram_slots = 0
        vmstate_dump_file = 0x0
        main_loop_err = 0x0
        err = 0x0
        __func__ = "main"