[Pkg-erlang-devel] Bug#939804: Bug#939804: erlang: FTBFS on hppa - escript: exception error: bad argument

[John David Anglin]

On 2019-09-09 9:12 a.m., Sergei Golovan wrote:
> #  define ERTS_STACK_LIMIT ((char *) ethr_get_stacklimit())
>
> static int
> stack_guard_downwards(void)
> {
>     char *limit = ERTS_STACK_LIMIT;
>     char c;
>
>     ASSERT(limit);
>
>     return erts_check_below_limit(&c, limit + ERTS_PCRE_STACK_MARGIN);
> }
>
> static int
> stack_guard_upwards(void)
> {
>     char *limit = ERTS_STACK_LIMIT;
>     char c;
>
>     ASSERT(limit);
>
>     return erts_check_above_limit(&c, limit - ERTS_PCRE_STACK_MARGIN);
> }
>
> void erts_init_bif_re(void)
> {
>     char c;
>     erts_pcre_malloc = &erts_erts_pcre_malloc;
>     erts_pcre_free = &erts_erts_pcre_free;
>     erts_pcre_stack_malloc = &erts_erts_pcre_stack_malloc;
>     erts_pcre_stack_free = &erts_erts_pcre_stack_free;
>     if ((char *) erts_ptr_id(&c) > ERTS_STACK_LIMIT)
>         erts_pcre_stack_guard = stack_guard_downwards;
>     else
>         erts_pcre_stack_guard = stack_guard_upwards;
>     default_table = NULL; /* ISO8859-1 default, forced into pcre */
>     max_loop_limit = CONTEXT_REDS * LOOP_FACTOR;
>
>     erts_init_trap_export(&re_exec_trap_export, am_erlang, am_re_run_trap, 3,
>                           &re_exec_trap);
>
>     grun_trap_exportp =  erts_export_put(am_re,am_grun,3);
>     urun_trap_exportp =  erts_export_put(am_re,am_urun,3);
>     ucompile_trap_exportp =  erts_export_put(am_re,am_ucompile,2);
>
>     return;
> }
>
> The code
>
>     if ((char *) erts_ptr_id(&c) > ERTS_STACK_LIMIT)
The above check is wrong.  ERTS_STACK_LIMIT is always NULL here resulting in stack_guard_downwards
always being selected.  erts_init_bif_re is called before the stack limit is set.  Think we need a different
stack direction check.
>         erts_pcre_stack_guard = stack_guard_downwards;
>     else
>         erts_pcre_stack_guard = stack_guard_upwards;
>
> has been introduces in version 20, and it is used to protect stack
> during PCRE calls.
> It seems that this stack protection doesn't work for hppa and always
> fails. As a result,
> every call to a regexp routine fails.

Dave

-- 
John David Anglin  dave.anglin at bell.net