Thread 2 "thr_lock" received signal SIGSEGV, Segmentation fault.

[Switching to Thread 0x7ffff7fcd700 (LWP 30979)]

0x0000000000402bc8 in thr_lock_info_init (info=0x7ffff7fccc38, tmp=0x0) at thr_lock.c:472

472	  info->thread=    tmp->pthread_self;

(gdb) bt

#0  thr_lock_info_init (info=0x7ffff7fccc38, tmp=0x0) at thr_lock.c:472

#1  test_thread (arg=0x7fffffffdef0) at thr_lock.c:1809

#2  start_thread (arg=<optimized out>) at pthread_create.c:486

#3  clone () at clone.S:95

(gdb) p tmp

$2 = (struct st_my_thread_var *) 0x0