Re: gmake segfaults with netbsd32 compat

[Pierre Pronchery <khorben%defora.org@localhost>]

			Hey there,

On 15/09/2016 21:04, coypu%SDF.ORG@localhost wrote:
> On Thu, Sep 15, 2016 at 06:27:01PM +0200, Pierre Pronchery wrote:
> > On 09/15/16 08:44 AM, coypu%SDF.ORG@localhost wrote:
> > > building with everything i386 except amd64 kernel or in i386 chroot and
> > > amd64 host I have gmake repeatedly segfaulting. so much that I resorted
> > > to using `while true; do make install; done` to get through building
> > > packages.
> > >
> > > I don't recall having such trouble with all i386 and switching back to
> > > it seems to help a lot.
> > >
> > > anyone seeing the same?
> >
> > Are you using PaX mprotect? Try to "paxctl +m gmake" just in case.
>
> Seems to be doing much better after
>    paxctl +a `which gmake`

Right, it's an issue with ASLR not mprotect; I mis-remembered.

> Interesting it works well on i386, works well on amd64, but not in amd64
> kernel with i386 userland.
>
> When I looked around, I noticed it is making calls like
> remake.c:319-320
>
>        /* Clean up any alloca() used during the update.  */
>        alloca (0);
>
> The Internet told me "don't do that". Would that be possibly related?

No, the underlying issue is documented there:
http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=50469

I committed a fix to -current (with help from xtos@) and asked for a 
pull-up to NetBSD 7 but martin@ thinks the fix is not correct. He knows 
better so I did not insist after that.

It works just fine in EdgeBSD though :)

HTH,
--
khorben