On Thu, Jan 04, 2018 at 09:36:27PM -0800, John Reiser wrote:
2) The explicit write by the stack probe can mask a
memcheck(valgrind)
violation, at least until memcheck groks the probe.
That should not be true. The probe is done after the stack pointer is
lowered, so memcheck/valgrind knows that memory is used. If the probe
is done below the actual stack pointer that would be a bug in the gcc
-fstack-protector implementation. Please do report such issues when you
encounter them. There were indeed such bugs in the past on some
architectures (especially in combination with no-return functions),
but I believe they have all been fixed now.
Thanks,
Mark