Segmentation Fault in signer due to changing config pointer

Although I haven't set tsig in addns.xml and assumed that its object should be NULL, it gets a value somewhere in the code.

Here is the output of valgrind:
==768== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==768== General Protection Fault
==768== at 0x441310: xfrd_tsig_process (xfrd.c:595)
==768== by 0x442DDD: xfrd_parse_packet (xfrd.c:1057)
==768== by 0x443613: xfrd_handle_packet (xfrd.c:1193)
==768== by 0x44485C: xfrd_tcp_read (xfrd.c:1516)
==768== by 0x4460E2: xfrd_handle_zone (xfrd.c:1997)
==768== by 0x4350FE: netio_dispatch (netio.c:328)
==768== by 0x4115E7: xfrhandler_start (xfrhandler.c:123)
==768== by 0x411FF7: xfrhandler_thread_start (engine.c:243)
==768== by 0x5FAC181: start_thread (pthread_create.c:312)
==768== by 0x56FA47C: clone (clone.S:111)