On Tue, Jun 07, 2011 at 11:01:53PM +0100, Owain Ainsworth wrote:
> On Tue, Jun 07, 2011 at 06:51:31PM +0200, Christian Ehrhardt wrote:
> > Hi,
> >
> > while reading through uvm code I stubled accross a piece of code that
> > appears to be buggy. Here's the proposed patch, rational follows:
> >
> > Index: uvm_vnode.c
> > ===================================================================
> > RCS file: /cvs/src/sys/uvm/uvm_vnode.c,v
> > retrieving revision 1.71
> > diff -u -r1.71 uvm_vnode.c
> > --- uvm_vnode.c 18 May 2010 04:41:14 -0000 1.71
> > +++ uvm_vnode.c 7 Jun 2011 16:42:15 -0000
> > @@ -924,8 +924,8 @@
> > */
> >
> > if (flags & PGO_DEACTIVATE) {
> > - if ((pp->pg_flags & PQ_INACTIVE) == 0 &&
> > - pp->wire_count == 0) {
> > + if ((ptmp->pg_flags & PQ_INACTIVE) == 0 &&
> > + ptmp->wire_count == 0) {
> > pmap_page_protect(ptmp,
> VM_PROT_NONE); >
> uvm_pagedeactivate(ptmp); > }
>
> This does look correct to me. In very *very* rare cases where one page was
> wired and the other was not (playing with mlock() could cause this
> synthetically with luck) this could cause us to hit a KASSERT in
> uvm_pagedeactivate().
>
> Note that the PQ_INACTIVE bit isn't needed (pagedeactivate already
> checks that) but the wire count check is still necessary.
>
> Anyone willing to ok this diff? I'll take care of it.
ok
--
Ariane
