Shadow stack backtrace command name

[Florian Weimer]

* Christina via Gdb Schimpe:

> However, based on the use cases that I am aware of, I am not sure if
> the user wants to always see the shadow stack bt in the ordinary bt
> output (if shadow stack is enabled).

Based on my experiments, Linux currently does not push the instruction
pointer onto the shadow stack if code is interrupted by a signal.  It
still works because the return mechanism is different.  This would be a
very visible difference between ordinary backtraces and shadow stack
based backtraces.

As far as I understand it, the kernel could change, and it may still be
early enough to make this change.

By the way, is there a way to tell if a process is in shadow stack mode
using upstream GDB today?  Preferably something that does not rely on
glibc internals?

Thanks,
Florian