Eric W. Biederman wrote:

- Removal of sys_sysctl support where people had used conflicting sysctl
  numbers. Trying to break glibc or other applications by changing the
  ABI is not cool.  9 instances of this in the kernel seems a little
  extreme.

It would be highly advantageous if we could have a file that acts as a 
central registry of architectural sysctl numbers *and have the numbers 
in the kernel derived from there*.  As I've said before, I don't really 
think sys_sysctl is any worse than ad hoc system calls (sys_mips and the 
like), but the real problem is that there are architectural and 
non-archtectural numbers, and they're mixed in all over the place.

I think it would be fair to say that if they're not in <linux/sysctl.h> 
they're not architectural, but that doesn't resolve the counterpositive 
(are there sysctls in <linux/sysctl.h> which aren't architectural?  From 
the looks of it, I would say yes.)  Non-architectural sysctl numbers 
should not be exported to userspace, and should eventually be rejected 
by sys_sysctl.

	-hpa