From: Rich Felker <dalias@libc.org>
To: Eli Zaretskii <eliz@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: Dumper issue, revisited; invalid realloc/free
Date: Wed, 4 Feb 2015 14:13:05 -0500 [thread overview]
Message-ID: <20150204191305.GY23507@brightrain.aerifal.cx> (raw)
In-Reply-To: <83pp9pfqb3.fsf@gnu.org>
On Wed, Feb 04, 2015 at 09:08:00PM +0200, Eli Zaretskii wrote:
> > Date: Wed, 4 Feb 2015 12:57:09 -0500
> > From: Rich Felker <dalias@libc.org>
> >
> > The simplest solution I can find is to make the affected free
> > functions (xrealloc, xfree, lisp_free, and lisp_align_free) check
> > whether their argument is in the range of data_start...initial_brk and
> > act as a nop (or in the case of xrealloc, allocate a new object
> > without freeing the old one) when this is the case. The check is
> > easily accomplished by saving initial_brk=sbrk(0) at startup (to be
> > lazy I did this with attribute((constructor)) but other approaches
> > might be preferred for an upstream fix. For xrealloc, since the old
> > size is not known, I simply estimate it as initial_brk-block. Copying
> > up to the min or this value and the new size should be safe, anyway.
> >
> > Does this sound acceptable for upstream?
>
> Yes. Several platforms (Cygwin and MinGW on MS-Windows) already do
> exactly that.
Where is the code that does this? I don't see it in alloc.c. Is it
only used when system_malloc=no? The case where it's really needed is
for system_malloc=yes...
Rich
next prev parent reply other threads:[~2015-02-04 19:13 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-04 17:57 Dumper issue, revisited; invalid realloc/free Rich Felker
2015-02-04 19:08 ` Eli Zaretskii
2015-02-04 19:13 ` Rich Felker [this message]
2015-02-04 19:22 ` Eli Zaretskii
2015-02-04 19:26 ` Eli Zaretskii
2015-02-04 20:34 ` Ken Brown
2015-02-05 1:31 ` Rich Felker
2015-02-05 3:25 ` Rich Felker
2015-02-05 3:48 ` Eli Zaretskii
2015-02-05 4:33 ` Rich Felker
2015-02-05 16:14 ` Wolfgang Jenkner
2015-02-05 18:43 ` Rich Felker
2015-02-04 19:21 ` Eli Zaretskii
2015-02-04 19:37 ` Rich Felker
2015-02-04 19:44 ` Eli Zaretskii
2015-02-04 19:49 ` Rich Felker
2015-02-04 19:54 ` Eli Zaretskii
2015-02-04 20:02 ` Rich Felker
2015-02-04 20:36 ` Eli Zaretskii
2015-02-04 20:08 ` Rich Felker
2015-02-04 20:40 ` Eli Zaretskii
2015-02-04 22:17 ` Rich Felker
2015-02-05 3:42 ` Eli Zaretskii
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