Re: [Gcl-devel] segfault at startup

[Camm Maguire]

Greetings!  This is not a bug in gcl, but a design decision in the
memory management system, i.e. to rely on the long established
(decades old) specification of the brk system call to return memory
contiguously allocated from the end of the program's .data section.
Fedora has broken this spec in the name of security.  Not that there
aren't arguable reasons for abandoning brk in the hostile computing
environment of today, but in email correspondence on the issue, one of
the very helpful Fedora developers had admitted thinking it was wrong
to break brk.

I've just downloaded the source to setarch, and if I can get access
again to a FC1 box, I'll put the necessary syscall into gcl proper for
greater user transparency.  One can only hope that this method of
disabling exec-shield for a given executable won't be going away
someday too.

It should be noted that gcl itself can likely survive brk
randomization, though at significant loss in memory available to the
user.  Its emacs' unexec, used by GCL, which is truly broken and would
need 'fixing' for this issue to completely go away.  I've been told
that people are working on this.

Take care,

"Jonathan Hudson" <address@hidden> writes:

> gcl 2.5.3 segfaults when it starts up unless
> I make and run it with
> 
> setarch i386 make 
> 
> and  
> 
> setarch i386 gcl
> 
> I'm running Fedora Core 1 on a Dell Inpiron 4000.
> It worked without the setarch command under red hat 9.
> I reported this to the fedora bugzilla first and i was told
> it was probably a bug in gcl because of the randomization of memory
> introduced used the fedora kernel.
> 
> Jonathan
> 
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> 

-- 
Camm Maguire                                            address@hidden
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