0x00007ffff6a154e8 in pthread_mutex_lock@plt () from /nix/store/pqrv50qg4znpr58r1snl47pmwnabqwlk-gnustep-libobjc2-svn/lib/libobjc.so.4.6 (gdb) bt #0 0x00007ffff6a154e8 in pthread_mutex_lock@plt () from /nix/store/pqrv50qg4znpr58r1snl47pmwnabqwlk-gnustep-libobjc2-svn/lib/libobjc.so.4.6 #1 0x00007ffff6a187f8 in dtable_for_class (cls=0xe181c0) at /tmp/nix-build-gnustep-libobjc2-svn.drv-0/gnustep-libobjc2/dtable.h:66 #2 classHasDtable (cls=) at /tmp/nix-build-gnustep-libobjc2-svn.drv-0/gnustep-libobjc2/dtable.h:110 #3 mergeMethodsFromSuperclass (super=0x602550 <_OBJC_CLASS_MLTestClass>, cls=, methods=0x1009380) at /tmp/nix-build-gnustep-libobjc2-svn.drv-0/gnustep-libobjc2/dtable.c:529 #4 0x00007ffff6a18c93 in add_method_list_to_class (cls=0x602550 <_OBJC_CLASS_MLTestClass>, list=) at /tmp/nix-build-gnustep-libobjc2-svn.drv-0/gnustep-libobjc2/dtable.c:573 #5 0x00007ffff6a1dba8 in class_addMethod (cls=0x602550 <_OBJC_CLASS_MLTestClass>, name=, imp=, types=) at /tmp/nix-build-gnustep-libobjc2-svn.drv-0/gnustep-libobjc2/runtime.c:195 #6 0x000000000040121b in main () at 2.m:45