my understanding is that malloc shouldn't be used in signals. is that correct?

(1) ostream is used in printStackTrace(). does ostream call malloc? I imagine so.
(2) backtrace_symbols() probably calls malloc()?
(3) printStackTrace() calls free()

so what to do, as a stack trace might be helpful. one option is just make sure anything "important" is done first, and that stdout is flushed, and then just try it. (1) and (3) could be eliminated but perhaps #2 is hard.