I am also rebuilt VM with full debug into (as specified in HowToBuild) hoping to get some more info, but got the same results :(
Even core dump can't help much:
Core was generated by `./lib/squeak/3.9-7/squeak PharoCore-1.2-12159.image'. Program terminated with signal 11, Segmentation fault. #0 0x009012db in ?? () (gdb) bt #0 0x009012db in ?? () #1 0x00906fc0 in ?? () #2 <signal handler called> #3 0x00754701 in ?? () #4 0x00755470 in ?? () #5 0x0074d80e in ?? () #6 0x00bec7ee in ?? () (gdb) info threads 2 Thread 12620 0x08085c02 in ?? () * 1 Thread 12623 0x009012db in ?? ()