Experimental ttwwakeup() panic patch

[Ed Maste]

On Wed, May 11, 2005 at 08:36:08PM -0700, Doug White wrote:

> This is a problem mlaier and I may have fixed, at least against -CURRENT.
> It appears that the process group alias in struct tty is accessed without
> locking and its changing out from under us.
> 
> Give this a try:
> 
> http://people.freebsd.org/~mlaier/tty.t_pgrp.diff
> 
> It compiles but I haven't actually booted a kernel with it, so YMMV.

I applied the patch to our mostly-5.3 tree (with some modifiecations to
ttyinfo() to get it to apply).

It boots and passed the test that provoked the issue before.  The crash
only showed up on one nightly testrun out of dozens though, so I'm not
certain it fixes the underlying issue.

I'll let you know if anything else turns up.

--
Ed Maste, Sandvine Incorporated