Re: Fwd: brk randomization breaks columns

From: Abel Bernabeu
Date: Mon Feb 04 2008 - 16:55:11 EST


2008/2/4, Pavel Machek <pavel@xxxxxx>:
> > >
> > > > I still don't seem to fully understand what is happening here --
> > > > aparently this is triggerable only with old programs linked against
> > > > libc.so.5, and I am not able to trigger it with my trivial program when
> > > > I link it against old libc.so.5, which just basically does brk() and
> > > > checks whether /proc/<pid>/maps are OK. Seems to me that (at least
> > > > certain versions) of libc.so.5 (wrongly) assume that end of the bss is
> > > > the start of the heap, but I will try to investigate it more.
> >
> > I think I am getting the some problem with brand new binaries produced
> > by myself :(
> >
> > Look at this report I posted days ago:
> >
> > http://marc.info/?l=linux-kernel&m=120169141603789&w=2
>
> Your crash is in kernel, no? Anyway, I can workaround mine by
> disabling randomization...

Yes, my crash happens at kernel space, but is due to the randomized
params passed to set_brk (the same thing that makes your game crash
later at runtime).

I did not understand why my kernel was crashing before reading your
comments, but now I think is all happening because of the brk
randomization. Sorry, I will not be able to try disabling
randomization until tomorrow at office in order to confirm you this.

I am trying to figure out what is relation the brk randomization
feature and my crash... but makes sense to me now, trying to find it.

Yours, Abel.
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