Program received signal SIGSEGV, Segmentation fault. [Switching to Thread -145934672 (LWP 2582)] 0x081276e5 in low_object_index_no_free (to=0xffaaad58, o=0x88bfa78, f=67) at /root/Pike-v7.8.352/src/object.c:1252 1252 add_ref(to->u.dummy=dummy);
Looks like some kind of refcount error on the thing stored in identifier # 67 in the object o. I suggest you try to identify that thing and see if it's been in suspicious places. To begin with you can compile --with-rtldebug and use describe(o) to see what that object is and what the variable in identifier # 67 is.
Running with valgrind and/or --with-dmalloc-debug provides a sort of catch-all harness which may trig the error closer to the source, but both add a significant overhead.