Re: [PATCH] libgomp: fix hang on fatal error

[Jakub Jelinek <jakub@redhat.com>]

On Wed, Oct 19, 2022 at 03:27:52PM +0200, Jakub Jelinek via Gcc-patches wrote:
> > --- a/libgomp/error.c
> > +++ b/libgomp/error.c
> > @@ -77,7 +77,7 @@ void
> >  gomp_vfatal (const char *fmt, va_list list)
> >  {
> >    gomp_verror (fmt, list);
> > -  exit (EXIT_FAILURE);
> > +  abort ();
> >  }
> >  
> >  void
> 
> I don't like this, abort has quite different user visible behavior
> from exit, e.g. the former often dumps core.
> 
> I believe in most places libgomp handles this by releasing locks before
> calling gomp_{,v}fatal:
>       gomp_mutex_unlock (&register_lock);
>       gomp_fatal ("Out of memory allocating %lu bytes", (unsigned long) size);
> 
>       gomp_mutex_unlock (&devicep->lock);
>       gomp_fatal ("Copying of %s object [%p..%p) to %s object [%p..%p) failed",
>                   src, srcaddr, srcaddr + size, dst, dstaddr, dstaddr + size);
> 
> etc.
> I could live with a gomp_fatal/gomp_vfatal alternative that would
> use _exit/_Exit (but not sure if it is supported on all targets where
> libgomp is) for uses where releasing locks is for whatever reason
> not an option.

Or yet another possibility would be not use gomp_fatal from within the
plugins, but use gomp_error instead and through possibly adjusted plugin
APIs tell libgomp that there was a fatal error and let libgomp unlock
anything that needs unlocking and exit (EXIT_FAILURE); afterwards.

	Jakub