On Fri, 08 May 1998 11:59:10 +0100 
 "Neil A. Carson" <neil@causality.com> wrote:

 > >         - Serious bugs in Mach VM will be, and have been, fixed (e.g. the
 > >           mmap security bug some months ago, other major problems).  Don't
 > >           make blanket statements about NetBSD Project policy unless you're
 > >           in a position to do so (and, I can say with reasonable authority,
 > >           you are not).
 > 
 > I am only reiterating a statement made on tech-kern a week or so ago, in
 > the discussion about the X-server 'leaks.' Did you send them a stroppy
 > message too?

Neil,

The message on tech-kern was with regard to one of the "non-critical bugs
due to Mach VM's design" I was referring to.  Given the nature of the
problem, and the relative severity (i.e. "not very"), it simply isn't worth
investing the time resources into fixing that particular problem.  I think
this is completely justified... when John Dyson "fixed" this problem in
FreeBSD (after it was pointed out on tech-kern@netbsd.org), his "fix"
actually introduced more bugs.  It took several iterations before he got
it to work even close to correctly.

Rather, we should spend that time getting the stragglers converted to
UVM, where this is simply not a problem.

By no means have we stated that bugs in Mach VM won't be fixed... if someone
found a serious bug in the Mach VM swap pager tomorrow, we would fix it,
because some ports are still using it.

Anyhow, I don't know what else say except that your statement that "NetBSD
will not fix any more bugs in Mach VM" was false.  It's simply a matter
of choosing between which bugs we fix directly and which bugs we fix by
saying "not an issue in the new VM system; please get the port switched
over".

Now, I was especially annoyed at your statement because it of your apparent
hand-waving at the problem.  From my perspective, it certainly appeared
as if you were saying - "Since it works in FreeBSD, it must be a bug in
the NetBSD VM system."  That, I think, is not a very constructive attitude.
In fact, there is reasonable evidence that it (the example cited in the mail
I responded to) does in fact work fine in the NetBSD VM system provided that
the platform-specific code (the pmap module) provides the right information.

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                            Home: +1 408 866 1912
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