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bug#26961: 26.0.50; Possible timming issue in regex-tests.el
From: |
Tino Calancha |
Subject: |
bug#26961: 26.0.50; Possible timming issue in regex-tests.el |
Date: |
Fri, 19 May 2017 20:38:40 +0900 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) |
Eli Zaretskii <eliz@gnu.org> writes:
>> + AUTO_STRING (inner_format, "`?%c'");
>> CALLN (Fmessage,
>> format, file,
>> - Fmapconcat (Qstring,
>> + Fmapconcat (list3 (Qlambda, list1 (Qchar),
>> + list3 (Qformat, inner_format, Qchar)),
>> Fsort (Vlread_unescaped_character_literals, Qlss),
>> separator));
>> }
>>
>> Do you think this code is wrong?
>
> This does indeed look dangerous: we are in effect consing Lisp data
> structures from stack-based Lisp objects, and then process them in a
> way that could leave some of them lying around when this function
> returns, and its stack becomes invalid.
>
> Can you present the evidence that caused you to suspect this
> particular change? Were the "unescaped character literals" warning
> displayed during the session which crashed?
Yes, such warning always appear in the crash session.
Loading â/home/calancha/soft/emacs-master/test/src/regex-tests.elâ:
unescaped character literals `?;' detected!
Running 22 tests (2017-05-19 20:24:31+0900)
If i print out the string, when the object is a cons with its car the string
to print, as follows:
--8<-----------------------------cut here---------------start------------->8---
diff --git a/src/alloc.c b/src/alloc.c
index faa14eebb3..20cfb3c88e 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -6664,7 +6664,32 @@ mark_object (Lisp_Object arg)
cdr_count = 0;
goto loop;
}
- mark_object (ptr->car);
+ po = XPNTR (ptr->car);
+ switch (XTYPE (ptr->car))
+ {
+ case Lisp_String:
+ {
+ if (!STRING_MARKED_P (XSTRING (ptr->car)) &&
+ !PURE_P (po) &&
+ mem_find (po) == MEM_NIL)
+ {
+ fprintf (stderr, "[ERROR] mem_find (po) = MEM_NIL, cons %p
car %s cdr %p\n",
+ ptr, XSTRING (ptr->car)->data, XPNTR (ptr->u.cdr));
+ return;
+ }
+ else
+ {
+ fprintf (stderr, "[OK] cons %p car %s cdr %p\n",
+ ptr, XSTRING (ptr->car)->data, XPNTR (ptr->u.cdr));
+ }
+ break;
+ }
+ default:
+ {
+ mark_object (ptr->car);
+ }
+ }
+ mark_object (ptr->car);
obj = ptr->u.cdr;
cdr_count++;
if (cdr_count == mark_object_loop_halt)
--8<-----------------------------cut here---------------end--------------->8---
Then, i see that right before the crash, the string printed out is the name
of the test file containinig the unescaped characters.
[OK] cons 0x2f0a8f0 car
/home/calancha/soft/emacs-master/test/src/regex-resources/BOOST.tests cdr
0x2f0a8e0
[ERROR] mem_find (po) = MEM_NIL, cons 0x2f45150 car cdr 0x2f45140
[OK] cons 0x16d8720 car
/home/calancha/soft/emacs-master/test/src/regex-resources/PCRE.tests cdr
0x16d8730
[ERROR] mem_find (po) = MEM_NIL, cons 0x2f45150 car cdr 0x2f45140
[OK] cons 0x3009910 car
/home/calancha/soft/emacs-master/test/src/regex-resources/PTESTS cdr 0x3009900
[ERROR] mem_find (po) = MEM_NIL, cons 0x2f45150 car cdr 0x2f45140
With:
Fmapconcat (Qstring,
insted of:
Fmapconcat (list3 (Qlambda, list1 (Qchar),
list3 (Qformat, inner_format, Qchar)),
we still see the warning, as we should because the test file contains
those chars, but there is _no_ crash.
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Tino Calancha, 2017/05/17
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Tino Calancha, 2017/05/17
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Eli Zaretskii, 2017/05/17
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Tino Calancha, 2017/05/18
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Andreas Schwab, 2017/05/18
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Eli Zaretskii, 2017/05/18
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Tino Calancha, 2017/05/18
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Eli Zaretskii, 2017/05/19
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el,
Tino Calancha <=
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Eli Zaretskii, 2017/05/20
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Tino Calancha, 2017/05/20
- bug#26961: 26.0.50; Possible timming issue in regex-tests.el, Eli Zaretskii, 2017/05/20