Re: MPS: a random backtrace while toying with gdb

[Eli Zaretskii <eliz@gnu.org>]

> From: Gerd Möllmann <gerd.moellmann@gmail.com>
> Cc: Eli Zaretskii <eliz@gnu.org>,  eller.helmut@gmail.com,
>   pipcet@protonmail.com,  emacs-devel@gnu.org
> Date: Mon, 01 Jul 2024 20:19:09 +0200
> 
> Ihor Radchenko <yantar92@posteo.net> writes:
> 
> >> If you really mean malloc, then there usually is not problem because
> >> signal handlers cannot safely call malloc.  And if malloc causes GC,
> >> see above.
> >
> > I do not mean calling malloc. I mean, what happens if a signal arrives
> > _while_ malloc is still in the process of allocating data?
> 
> One would have to consult the malloc implementation. Portably, it's not
> safe to call malloc in a signal handler.

Right.  Also, keep in mind that as long as malloc didn't finish its
job of serving a call, the memory it was requested to allocate is not
yet available to the program, and thus no one except malloc itself can
access that memory.