Re: [announce] [patch] NX (No eXecute) support for x86,2.6.7-rc2-bk2

[Doug McNaught]

Arjan van de Ven <arjanv@xxxxxxxxxx> writes:

> On Wed, Jun 02, 2004 at 02:13:13PM -0700, Linus Torvalds wrote:
>> 
>> 
>> Just out of interest - how many legacy apps are broken by this? I assume 
>> it's a non-zero number, but wouldn't mind to be happily surprised.
>
> based on execshield in FC1.. about zero.

IIRC, Lisp systems like CMUCL and SBCL (plus commercial Lisps) had
problems with FC1 due to execshield.  They tend to do things like
compile code on the fly to heap memory and expect to be able to run
it.

>> And do we have some way of on a per-process basis say "avoid NX because
>> this old version of Oracle/flash/whatever-binary-thing doesn't run with
>> it"?
>
> yes those aren't compiled with the PT_GNU_STACK elf flag and run with the
> stack executable just fine. GCC will also emit a "make the stack executable"
> flag when it emits code that puts stack trampolines up.
> That all JustWorks(tm).

Given this I wonder why they had trouble...

Disclaimer: I don't hack on free Lisps; I just follow some of the
mailing lists, so I may have important details wrong.  :)

-Doug
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