Segfault during GC

[brendon9x]

I'm struggling with this one. I'm getting these errors exclusively in the app I'm trying to use it with:

(gdb) backtrace
#0 0x00007fff81f63616 in __kill ()
#1 0x00007fff82003cca in abort ()
#2 0x00007fff81f1b6f5 in free ()
#3 0x00000001007b855a in bitset_free (bs=0x10756b280) at bitset.c:28
#4 0x000000010003aead in run_final (obj=4384258840) at gc.c:1955
#5 0x000000010003aede in finalize_list (p=0x105527b18) at gc.c:1097

...

I've been starting at the code for an hour and bashing it from every angle, but it refuses to die under any spec I write.

Any ideas?