Sleeping thread held mutex in vm_pageout_oom()

[Konstantin Belousov]

On Thu, Jan 22, 2015 at 07:30:19PM -0500, Ryan Stone wrote:
> Other than the redundant braces on the else below, this looks good.  I
> tested it today and saw no further problems.
The (possibly implicit) style rule is to have {} around both branches
in if () when one branch requires {}.

> 
> I do think that a WITNESS_WARN() in vmspace_free() would be
> appropriate.  I'll give that a sanity here to make sure that nothing
> explodes and if everything looks ok, I'll commit it.
Ok.

> 
> > @@ -1573,16 +1602,19 @@ vm_pageout_oom(int shortage)
> >                  */
> >                 if (size > bigsize) {
> >                         if (bigproc != NULL)
> > -                               PROC_UNLOCK(bigproc);
> > +                               PRELE(bigproc);
> >                         bigproc = p;
> >                         bigsize = size;
> > -               } else
> > -                       PROC_UNLOCK(p);
> > +               } else {
> > +                       PRELE(p);
> > +               }