* suspected use-after-free leads to bootstrap failure
@ 2011-03-31 9:37 Jim Meyering
2011-03-31 18:46 ` Eli Zaretskii
0 siblings, 1 reply; 2+ messages in thread
From: Jim Meyering @ 2011-03-31 9:37 UTC (permalink / raw)
To: emacs-devel, bug-gnu-emacs; +Cc: Stefan Monnier
Jim Meyering wrote:
> Eli Zaretskii wrote:
>>> From: Jim Meyering <jim@meyering.net>
>>> Date: Wed, 30 Mar 2011 09:42:42 +0200
>>> Cc: eggert@cs.ucla.edu, emacs-devel@gnu.org
>>>
>>> This command,
>>> env MALLOC_PERTURB_=0 MALLOC_CHECK_=0 make -j9 bootstrap
>>> has succeeded for me on each of the last three mornings (Mar 28-30).
>>>
>>> I manually set those two MALLOC_*_ variables to 0 because
>>> when I don't, emacs fails to bootstrap.
>>
>> It's a pity this problem was not reported to the bug tracker. (At
>> least I couldn't find it; apologies if I missed it.)
>
> I thought I reported it to some emacs development list months ago,
> but a quick search didn't find it.
>
>>> I suspect that emacs is using free'd memory containing
>>> values that would normally be unoffensive, but when you set
>>> those envvars (esp MALLOC_PERTURB_) to nonzero, it makes
>>> glibc scribble on free'd buffers, and that makes emacs
>>> exhibit an actual failure.
>>
>> Can you use bisect to find the guilty commit?
>
> Finding a commit for which a perturbed "make bootstrap" succeeds
> was a challenge.
>
> I bootstrapped 8 or 10 times, going back to 2009
> in steps of 500, then 1500 commits. Same failure
> each time, until I started getting link errors:
>
> /usr/bin/ld: xftfont.o: undefined reference to symbol 'XRenderQueryExtension'
> /usr/bin/ld: note: 'XRenderQueryExtension' is defined in DSO /usr/lib64/libXrender.so.1 so try adding it to the linker command line
> /usr/lib64/libXrender.so.1: could not read symbols: Invalid operation
>
> I worked around that by inserting -lXrender into the generated Makefile:
>
> perl -pi -e 's/(-lfreetype )/$1-lXrender /' src/Makefile
>
> With that, I finally found a successful build at this git commit:
>
> commit 84655cfe88efb24c256302d016cd037d22544cca
> Author: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Fri Nov 6 18:47:48 2009 +0000
>
> Let integers use up 2 tags to give them one extra bit and double their range.
> * lisp.h (USE_2_TAGS_FOR_INTS): New macro.
> (LISP_INT_TAG, case_Lisp_Int, LISP_STRING_TAG, LISP_INT_TAG_P): New macros.
> ...
>
> Maybe someone else will do the actual bisection:
>
> Bisecting: 4164 revisions left to test after this (roughly 12 steps)
>
> This is the command to run:
>
> env MALLOC_PERTURB_=44 MALLOC_CHECK_=3 make -j9 bootstrap
>
> If not, I'll get to it, eventually.
I did that.
This is the offending commit:
5a98a2a69b1a15173ce4bfa53307608a7150b407 is the first bad commit
commit 5a98a2a69b1a15173ce4bfa53307608a7150b407
Author: Stefan Monnier <monnier@iro.umontreal.ca>
Date: Sun Apr 18 17:49:33 2010 -0400
Hash-cons pure data.
* alloc.c (Fpurecopy): Hash-cons if requested.
(syms_of_alloc): Update purify-flag docstring.
* loadup.el: Setup hash-cons for pure data.
Bootstrapping (with MALLOC_PERTURB_=44 MALLOC_CHECK_=3) from there,
I get this failure:
In toplevel form:
/e/emacs/lisp/language/thai-word.el:10738:5:Error: \
Memory exhausted--use C-x s then exit and restart Emacs
Bootstrapping from the one just before succeeds.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: suspected use-after-free leads to bootstrap failure
2011-03-31 9:37 suspected use-after-free leads to bootstrap failure Jim Meyering
@ 2011-03-31 18:46 ` Eli Zaretskii
0 siblings, 0 replies; 2+ messages in thread
From: Eli Zaretskii @ 2011-03-31 18:46 UTC (permalink / raw)
To: Jim Meyering; +Cc: bug-gnu-emacs, monnier, emacs-devel
> From: Jim Meyering <jim@meyering.net>
> Date: Thu, 31 Mar 2011 11:37:37 +0200
> Cc: Stefan Monnier <monnier@iro.umontreal.ca>
>
> Author: Stefan Monnier <monnier@iro.umontreal.ca>
> Date: Sun Apr 18 17:49:33 2010 -0400
>
> Hash-cons pure data.
> * alloc.c (Fpurecopy): Hash-cons if requested.
> (syms_of_alloc): Update purify-flag docstring.
> * loadup.el: Setup hash-cons for pure data.
>
> Bootstrapping (with MALLOC_PERTURB_=44 MALLOC_CHECK_=3) from there,
> I get this failure:
>
> In toplevel form:
> /e/emacs/lisp/language/thai-word.el:10738:5:Error: \
> Memory exhausted--use C-x s then exit and restart Emacs
>
> Bootstrapping from the one just before succeeds.
Thanks!
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2011-03-31 18:46 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-03-31 9:37 suspected use-after-free leads to bootstrap failure Jim Meyering
2011-03-31 18:46 ` Eli Zaretskii
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.