From: Hollis R Blanchard <hollis+@andrew.cmu.edu>
To: Peter Chang <weasel@cs.stanford.edu>
Cc: linuxppc-dev@lists.linuxppc.org
Subject: Re: dl-load.c (ld.so) bug??
Date: Tue, 22 Jun 1999 09:52:49 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.3.96L.990622094815.1625A-100000@unix47.andrew.cmu.edu> (raw)
In-Reply-To: <v04205405b394c1fe1645@[209.239.164.131]>
On Mon, 21 Jun 1999, Peter Chang wrote:
>
> At 23:09 -0400 06.21.1999, Daniel Jacobowitz wrote:
> >On Mon, Jun 21, 1999 at 10:48:12PM -0400, Hollis R Blanchard wrote:
> > >
> > > I have two even simpler test cases for you:
> > >
> > > int main(void){
> > > char *ptr=NULL;
> > > free(ptr);
> > > }
> >
> >Well, that one would probably segfault anyway (or at least, is not
> >guaranteed not to).
>
> Hmm... the docs taht I have say this:
>
[snip]
> If ptr is a null pointer, no action occurs.
[snip]
Right. In other words, that's legal and should not segfault.
> > > int main(void){
> > > char *ptr = (char *)malloc(100);
> > > }
> >
> >That one's a problem, though :)
>
> Why? Its allocating memory, but never freeing it. Its a leak, but not
> accessing things out of bounds. I haven't used ElectricFence, but its
> not going to catch a bounds error on this.
Try it. It segfaults. Add a free afterwords if you like. It still segfaults.
Add a printf in front of it, and that printf will never happen. The segfault
starts in __libc_start_main. It makes no sense, but anytime you put a malloc
or a free in a program, EFence makes it segfault (*before* running that malloc
or free).
-Hollis
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next prev parent reply other threads:[~1999-06-22 13:52 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-06-21 22:52 dl-load.c (ld.so) bug?? Troy Benjegerdes
1999-06-22 0:04 ` Hollis R Blanchard
1999-06-22 1:57 ` Troy Benjegerdes
1999-06-22 2:48 ` Hollis R Blanchard
1999-06-22 3:09 ` Daniel Jacobowitz
1999-06-22 4:36 ` Peter Chang
1999-06-22 13:52 ` Hollis R Blanchard [this message]
[not found] <Pine.LNX.3.96L.990622003119.5237E-100000@unix47.andrew.cmu.edu>
1999-06-22 4:39 ` Peter Chang
[not found] <199906231258.HAA25989@www.cedarnet.org>
1999-06-23 13:17 ` Geert Uytterhoeven
1999-06-23 14:19 ` Hollis R Blanchard
1999-06-23 14:32 ` Kevin Puetz
[not found] <Pine.LNX.4.04.9906211749280.27642-100000@narn.local.drgw.n et>
1999-06-23 14:37 ` Franz Sirl
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