Backtracing through segfaults is hard. The approach we use in glibc/GNU/Linux is a function called *_fallback_frame_state, which copies the saved registers on the stack into the unwinder data. However, this only works if you're using DWARF-style unwinder data, which is used in the EABI port of ARM. If you're not using EABI, you really need to write your own version of backtrace() that starts from a signal fram and unwinds through it. The SIGCONTEXT ctx that's passed to your segfault handler contains the registers at the point the segfault occurred, and you can unwind starting from there. Don't do this: void *fp = __builtin_frame_address (0); Instead, pull fp and sp out of the SIGCONTEXT ctx. Andrew.
