Why is my application seg faulting on a pthread mutex?

I am debugging an x64 application in Ubuntu Linux.

Gdb is telling me that the cause of a seg fault has something to do with taking pthread mutex.

Thread 1 "xxxx" received signal SIGSEGV, Segmentation fault.
__GI___pthread_mutex_lock (mutex=mutex@entry=0x8) at ../nptl/pthread_mutex_lock.c:65
65  ../nptl/pthread_mutex_lock.c: No such file or directory.

This is happening on a statement that attempts to take a lock using the C++11 concurrency library locking primitives.

Is this happening because I am missing some pthread related .so?