On Fri, 28 Sep 2007 19:53:35 +0100 Ralf Baechle <ralf@xxxxxxxxxxxxxx> wrote:
> On Fri, Sep 28, 2007 at 11:45:26AM -0700, Andrew Morton wrote:
>
> >
> > > The virtual address space argument of clear_user_highpage is supposed to
> > > be the virtual address where the page being cleared will eventually be
> > > mapped. This allows architectures with virtually indexed caches a few
> > > clever tricks. That sort of trick falls over in painful ways if the
> > > virtual address argument is wrong.
> >
> > yeah, but only if you're using a weird CPU architecture ;)
>
> I guess once I convinced your employer that weird CPU architectures
> deliver more punch for the watt they stop being so weird ;-)
<wonders what you've gone and done this time>
> > >
> > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > > index 84c795e..eab8c42 100644
> > > --- a/mm/hugetlb.c
> > > +++ b/mm/hugetlb.c
> > > @@ -42,7 +42,7 @@ static void clear_huge_page(struct page *page, unsigned long addr)
> > > might_sleep();
> > > for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) {
> > > cond_resched();
> > > - clear_user_highpage(page + i, addr);
> > > + clear_user_highpage(page + i, addr + i * PAGE_SIZE);
> > > }
> > > }
> > >
> >
> > I'll add this to the 2.6.23 queue. Is it needed in 2.6.22.x?
>
> It's totally theoretical atm, MIPS doesn't support hugetlb and I'm not
> even working on it. I just happened to spot the issue.
sparc64 might care about this bug.
Anyway, I'll plop it in 2.6.23.
