git: af949c590bd8 - main - Disable stack gap for ntpd during build.

[Cy Schubert]

In message <CAPv3WKeV1Oz8Gbv0LBFD03J6k3k+2XMBEvi28DuMM8LVq8cjrQ at mail.gmail.c
om>
, Marcin Wojtas writes:
> Hi Jess
>
> pt., 21 maj 2021 o 15:39 Jessica Clarke <jrtc27 at freebsd.org> napisał(a):
> >
> > On 21 May 2021, at 14:34, Marcin Wojtas <mw at FreeBSD.org> wrote:
> > >
> > > The branch main has been updated by mw:
> > >
> > > URL: https://cgit.FreeBSD.org/src/commit/?id=af949c590bd8a00a5973b5875d7e
> 0fa6832ea64a
> > >
> > > commit af949c590bd8a00a5973b5875d7e0fa6832ea64a
> > > Author:     Marcin Wojtas <mw at FreeBSD.org>
> > > AuthorDate: 2021-05-21 09:29:22 +0000
> > > Commit:     Marcin Wojtas <mw at FreeBSD.org>
> > > CommitDate: 2021-05-21 13:33:06 +0000
> > >
> > >    Disable stack gap for ntpd during build.
> > >
> > >    When starting, ntpd calls setrlimit(2) to limit maximum size of its
> > >    stack. The stack limit chosen by ntpd is 200K, so when stack gap
> > >    is enabled, the stack gap is larger than this limit, which results
> > >    in ntpd crashing.
> >
> > Isn’t the bug that the unusable gap counts as usage?
> >
> > Jess
> >
>
> An alternative solution was submitted
> (https://reviews.freebsd.org/D29832), so that to extend the limit for
> ntpd, but eventually it was recommended to simple disable the stack
> gap for it until it's fixed upstream (see the last comment in the
> linked revision).

D29832 doesn't work. D29832 addressed the *already solved* stack gap issue 
in ntpd. The problem people failed to realize was that it wasn't stack gap 
but PIE. Enabling PIE regardless of the stack gap sysctl setting always 
resulted in the error. Ultimately a sledgehammer approach was the only way 
to address it.


-- 
Cheers,
Cy Schubert <Cy.Schubert at cschubert.com>
FreeBSD UNIX:  <cy at FreeBSD.org>   Web:  https://FreeBSD.org
NTP:           <cy at nwtime.org>    Web:  https://nwtime.org

	The need of the many outweighs the greed of the few.