[PATCH] aarch64: Fix error messages for GCS and BTI incompatible modules

[Yury Khrustalev]

On Mon, Jan 05, 2026 at 03:51:23PM -0300, Adhemerval Zanella Netto wrote:
> 
> On 05/01/26 12:07, Yury Khrustalev wrote:
> > Hi Adhemerval,
> > 
> > ...
> > 
> > This is a good suggestion but on a closer inspection this approach
> > misses case where we have both non-empty program and l_name (it
> > corresponds to the situation when the issue is found in one of the
> > dependencies of a dynamically linked program), and we'd like to have a
> > nice message in this case that would include both program name and the
> > library name.
> > 
> > In general, this code is run when we have already failed and are trying
> > to make a nice error message. Does it matter if we do a bit more checks?
> > I also think current code looks a bit more readable. Maybe it would be
> > OK to leave this patch as is?
> > 
> 
> Indeed, I tried to restructure the code because the STR_NOT_EMPTY macro
> is misleading that l->l_name might be NULL (although not incorrect).
> Maybe something like then:
> 
>    if (program != NULL)
>      {
>        if (program[0] != '\0' && l->l_name[0] != '\0')
>          /* A program's dependency is not GCS compatible.  */
>          _dl_fatal_printf ("%s: %s: failed to turn on BTI protection\n",
>                            program, l->l_name);
>        if (program[0] != '\0')
>          /* The program itself is not GCS compatible.  */
>          _dl_fatal_printf ("%s: failed to turn on BTI protection\n", program);
> 
>        /* For static binaries, program will be an empty string.  */
>        _dl_fatal_printf ("error: failed to turn on BTI protection\n");
>      }
>    else
>      /* If program is NULL, we are processing a dlopen operation.
>         Note: the errno value is not available any more.  */
>      _dl_signal_error (0, l->l_name, "dlopen",
>                        "failed to turn on BTI protection");

Thanks for the feedback. I've sent v2 [1].

[1]: https://inbox.sourceware.org/libc-alpha/20260106111759.3785728-1-yury.khrustalev@arm.com/