On Wed, Jan 20, 2021 at 07:04:14PM +0100, Christian Jullien wrote:
> Fortunalety, OpenBSD has mquery specific call which does exactly what I need
> to find a valid start address.
> Porting a software is sometimes very easy, sometimes it needs some
> adaptations.
> I'm fine with mquery.
To state the obvious: your original code doing mmap(...MAP_FIXED...)
only works by accident on other systems. Due to address space size
and/or randomization differences your code just got lucky on those
systems.
Just don't use it mmap(...MAP_FIXED...).
-Otto
>
> Christian
>
> -----Original Message-----
> From: Theo de Raadt [mailto:[email protected]]
> Sent: Wednesday, January 20, 2021 18:01
> To: [email protected]
> Cc: 'Otto Moerbeek'; [email protected]
> Subject: Re: munmap sometimes does coredump on arm after mmap success
>
> > Even if the behavior is still strange for me, I accept how it behaves on
> > OpenBSD.
>
> mmap and munmap work the same on all systems.
>
> You are just less likely to replace used memory, which is relied upon.
>
>
