From: Theo de Raadt <deraadt@cvs.openbsd.org>
Subject: Re: ip sysctl atomic
To: alexander.bluhm@gmx.net, claudio@openbsd.org
Cc: mark.kettenis@xs4all.nl, tech@openbsd.org
Date: Fri, 17 May 2024 13:24:32 -0600

> e.g. when a function checks ip_forwarding and then calls a 2nd function
> which also checks ip_forwarding then you can't ensure that both see the
> same value. This can be a very nasty footgun.

Wait wait.  So you are talking about two seperate sysctl(2) invocations?

That's not atomic.  There is no chance of it being atomic.  That is
not solveable.