JIT breaks on feather3

[Mark Glines]

Geoffrey Broadwell wrote:
> Perhaps some security option is being set based on not having a "real"
> tty?

Hmm.  That's a good thought, something along those lines could 
definitely be the difference.  Unfortunately I don't see much difference 
between the ttys.  Outside of screen:

$ tty
/dev/ttyp9

Inside of screen:

$ tty
/dev/ttyp0


>> If it helps, feather3 is a virtual machine running Debian lenny/sid, 
>> kernel 2.6.18-6-xen-686, and libc6 version 2.7-15.
> 
> That's a pretty old kernel (from the previous stable release).  My
> Debian lenny/sid system reports a 2.6.26 kernel, and according to
> apt-cache linux-image-2.6-xen-686 is up to 2.6.26+16.  I'm not sure it
> makes a big difference, but Xen is developed fairly rapidly so there
> might be fixes to memory protection bits in between 2.6.18 and 2.6.26.

Might be, all the NX bit handling stuff is pretty new to linux kernels. 
  I don't know enough about xen to be able to say whether this would 
necessarily be a xen issue, or somehow caused by the parent kernel. 
(Or, still, how screen triggers it.)  I've asked Juerd for more info on 
the parent kernel and platform (the CPU looks 64-bit capable), but 
haven't gotten an answer yet.

Any ideas on how to further narrow down this issue?

Mark