(gdb) info stack
#0  0x00002b0ebb91f495 in raise () from /lib64/libc.so.6
#1  0x00002b0ebb920bfd in abort () from /lib64/libc.so.6
#2  0x00002b0eb93fc13d in ink_abort (message_format=0x2b0eb9422afc "%s:%d: failed assertion `%s`") at ink_error.cc:99
#3  0x00002b0eb93f95b2 in _ink_assert (expression=0x7da865 "t != 0", file=0x7da838 "/home/wkaras/TS4/iocore/eventsystem/I_Lock.h",
    line=407) at ink_assert.cc:37
#4  0x000000000053b044 in Mutex_lock (location=..., ahandler=0x0, m=0x2b0ec010f260, t=0x0)
    at /home/wkaras/TS4/iocore/eventsystem/I_Lock.h:407
#5  0x000000000055e074 in TSMutexLock (mutexp=0x2b0ec010f260) at InkIOCoreAPI.cc:289
#6  0x00002aaaaaecec48 in Test1::thread () at test_cppapi/test_cppapi.cc:31
#7  0x00002aaaaaed00f5 in std::_Bind_simple<void (*())()>::_M_invoke<>(std::_Index_tuple<>) (this=0x1a64d48)
    at /opt/rh/devtoolset-4/root/usr/include/c++/5.3.1/functional:1531
#8  0x00002aaaaaed0061 in std::_Bind_simple<void (*())()>::operator()(void) (this=0x1a64d48)
    at /opt/rh/devtoolset-4/root/usr/include/c++/5.3.1/functional:1520
#9  0x00002aaaaaed0000 in std::thread::_Impl<std::_Bind_simple<void (*())()> >::_M_run(void) (this=0x1a64d30)
    at /opt/rh/devtoolset-4/root/usr/include/c++/5.3.1/thread:115
#10 0x00002aaaaaed0170 in ?? () from /home/wkaras/TS4/tests/_sandbox/cppapi/ts/plugin/test_cppapi.so
#11 0x00002b0ebbc89aa1 in start_thread () from /lib64/libpthread.so.0
#12 0x00002b0ebb9d5bcd in clone () from /lib64/libc.so.6
(gdb)