The code in handle_signal() wasn't clearing the struct sigaction before passing it to sigaction().
This meant that we would block a random set of signals while executing the default handler, or jump to the uninitialized __sa_sigaction__ (instead of sa_handler).
Initialize properly as we do in setup_signal_handler().
struct sigaction action;
action.sa_handler = SIG_DFL;
+ action.sa_flags = 0;
+ sigemptyset(&action.sa_mask);
sigaction(sig, &action, NULL);
raised_signal = sig;