On 2019-09-09 9:12 a.m., Sergei Golovan wrote:
> Hi John,
>
> On Mon, Sep 9, 2019 at 2:13 PM John David Anglin <dave.ang...@bell.net> wrote:
>> If you know how to reduce one of these regexp problems, I could look again.
>> Debugging
>> across forks is problematic (i.e., the error doesn't occur in escript).
> I seem to find the problematic code. If you look into
> erts/emulator/beam/erl_bif_re.c then
> you'll find the following lines after line 66:
>
> #define ERTS_PCRE_STACK_MARGIN (10*1024)
>
> # 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)
> 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.
>
> After I remove the erts_pcre_stack_guard assignment, Erlang started to
> build on hppa
> just fine.
>
I added some printfs to the code.
thr_wrapper: stacksize=0x0
thr_wrapper: stacksize=0x0
thr_wrapper: stacksize=0x0
thr_wrapper: stacksize=0x10000
thr_wrapper: stacksize=0x10000
thr_wrapper: stacksize=0x10000
erts_init_bif_re: &c=0xf9730748 ERTS STACK LIMIT=0x0
erts_init_bif_re: &c=0xf9df6748 ERTS STACK LIMIT=0x0
erts_init_bif_re: &c=0xf90b0748 ERTS STACK LIMIT=0x0
erts_init_bif_re: &c=0xf908c748 ERTS STACK LIMIT=0x0
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x80000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
thr_wrapper: stacksize=0x28000
stack_guard_downwards: &c=0xf7778b08 limit=0xf77f7000 ERTS STACK LIMIT=0x2800
stack_guard_downwards: &c=0xf787eb08 limit=0xf78fd000 ERTS STACK LIMIT=0x2800
stack_guard_downwards: &c=0xf787eb08 limit=0xf78fd000 ERTS STACK LIMIT=0x2800
stack_guard_downwards: &c=0xf77fbb08 limit=0xf787a000 ERTS STACK LIMIT=0x2800
escript: exception error: bad argument
in function re:split/3
called as re:split(<<"<?xml version=\"1.0\" encoding=\"utf-8\"
?>\n<!DOCTYPE comref SYSTEM \"comref.dtd\">\n\n<comref>\n <header>\n
<copyright>\n <year>1996</year><year>2016</year>\n <holder>Ericsson
AB. All Right"...>>,
"\n",[])
make[1]: ***
[/home/dave/debian/erlang/erlang-22.0.7+dfsg/make/otp_release_targets.mk:47:
../xml/epmd.xml] Error 127
make[1]: *** Waiting for unfinished jobs....
It would seem to me that ERTS_STACK_LIMIT is incorrect. As a result,
stack_guard_downwards
is called instead of stack_guard_upwards.
It's also a bit odd that twd->stacksize in thr_wrapper is sometimes 0. Think
ethr_thr_create
needs looking at.
Dave
--
John David Anglin dave.ang...@bell.net
