It's going to require more than removing the hack due to the following:

/* Storage for the alternate signal stack.  */
static union
{
  char buffer[SIGSTKSZ];

  /* These other members are for proper alignment.  There's no
     standard way to guarantee stack alignment, but this seems enough
     in practice.  */
  long double ld;
  long l;
  void *p;
} alternate_signal_stack;

On Thu, Mar 4, 2021 at 6:48 AM Carol Bouchard <cbouchar@redhat.com> wrote:
Thank you.  I may very well do that.  

Carol

On Thu, Mar 4, 2021 at 4:57 AM Daniel P. Berrangé <berrange@redhat.com> wrote:
On Wed, Mar 03, 2021 at 03:13:29PM -0500, Carol Bouchard wrote:
> In our code base (restraint), we patch and recompile the m4 code base.
> https://github.com/tar-mirror/gnu-m4
> In their code, they have the following which fails to compile when SIGSTKSZ
> < 16384 is interpreted.
> This is going to be a challenge to make work.
>
> # define SIGSTKSZ 8192
> #ifndef SIGSTKSZ
> # define SIGSTKSZ 16384
> #elif HAVE_LIBSIGSEGV && SIGSTKSZ < 16384
> /* libsigsegv 2.6 through 2.8 have a bug where some architectures use
>    more than the Linux default of an 8k alternate stack when deciding
>    if a fault was caused by stack overflow.  */
> # undef SIGSTKSZ
> # define SIGSTKSZ 16384
> #endif

AFAICT libsigsegv 2.8 is a release dating from 2009, obsoleted by the
2.9 release in 2010.

I'd question whether this code really need to workaround a bug in
something that is 11 years old.

IOW, I'd suggest just deleting this hack entirely.


Regards,
Daniel
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