ASLR, W^X, and guard pages trigger processor traps that result in

ASLR, W^X, and guard pages trigger processor traps that result in
SIGILL, SIGBUS, SIGSEGV signals.  Make such memory violations visible
in lastcomm(1).  This also works if a programm tries to hide them
with a signal handler.  Manual kill -SEGV does not generate false
positives.
OK deraadt@