[Bug c++/77772] Segmentation fault when running an application with gdb

["antonio.poggiali at datalogic dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77772

--- Comment #5 from Antonio Poggiali <antonio.poggiali at datalogic dot com> ---
(In reply to Richard Biener from comment #4)
> This looks like a libc/loader issue to me.  My source points at
> 
> /* Initialize _r_debug if it has not already been done.  The argument is
>    the run-time load address of the dynamic linker, to be put in
>    _r_debug.r_ldbase.  Returns the address of _r_debug.  */
> 
> struct r_debug *
> internal_function
> _dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
> {
>   struct r_debug *r;
> 
>   if (ns == LM_ID_BASE)
>     r = &_r_debug;
>   else
>     r = &GL(dl_ns)[ns]._ns_debug;
> 
>   if (r->r_map == NULL || ldbase != 0)
> 
> and thus 'r' being NULL.

I confirm your analysis. My code (dl-debug.c) is the same of yours.