From: Yinghai Lu on
On Fri, Jun 4, 2010 at 2:10 PM, Adam Lackorzynski
<adam(a)os.inf.tu-dresden.de> wrote:
> free_early_partial must check the returned region of find_overlapped_early()
> whether it is a region at all. Otherwise the function will indefinitely
> loop.

do you have that hang really?

that stage we should not have blank slot in the middle.

Thanks

Yinghai Lu

>
> Signed-off-by: Adam Lackorzynski <adam(a)os.inf.tu-dresden.de>
> ---
> �kernel/early_res.c | � �5 +++--
> �1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/early_res.c b/kernel/early_res.c
> index 31aa933..9afcb4c 100644
> --- a/kernel/early_res.c
> +++ b/kernel/early_res.c
> @@ -341,10 +341,11 @@ void __init free_early_partial(u64 start, u64 end)
>
> �try_next:
> � � � �i = find_overlapped_early(start, end);
> - � � � if (i >= max_early_res)
> + � � � r = &early_res[i];
> +
> + � � � if (i >= max_early_res || !r->end)
> � � � � � � � �return;
>
> - � � � r = &early_res[i];
> � � � �/* hole ? */
> � � � �if (r->end >= end && r->start <= start) {
> � � � � � � � �drop_range_partial(i, start, end);
> --
> 1.7.1
> --
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From: Adam Lackorzynski on

On Fri Jun 04, 2010 at 17:00:02 -0700, Yinghai Lu wrote:
> On Fri, Jun 4, 2010 at 2:10 PM, Adam Lackorzynski
> <adam(a)os.inf.tu-dresden.de> wrote:
> > free_early_partial must check the returned region of find_overlapped_early()
> > whether it is a region at all. Otherwise the function will indefinitely
> > loop.
>
> do you have that hang really?
>
> that stage we should not have blank slot in the middle.

I did but I cannot manage to reproduce this now. I think this happens
when find_overlapped_early does not find a region, i.e. the given one
does not exist. Then it returns i == early_res_count which is smaller
than max_early_res (usually). Given that r->end == 0 this goes on
indefinitely. So the check would just be more robust with
i >= max_early_res || !r->end or i == early_res_count.

Adam

> > Signed-off-by: Adam Lackorzynski <adam(a)os.inf.tu-dresden.de>
> > ---
> > �kernel/early_res.c | � �5 +++--
> > �1 files changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/kernel/early_res.c b/kernel/early_res.c
> > index 31aa933..9afcb4c 100644
> > --- a/kernel/early_res.c
> > +++ b/kernel/early_res.c
> > @@ -341,10 +341,11 @@ void __init free_early_partial(u64 start, u64 end)
> >
> > �try_next:
> > � � � �i = find_overlapped_early(start, end);
> > - � � � if (i >= max_early_res)
> > + � � � r = &early_res[i];
> > +
> > + � � � if (i >= max_early_res || !r->end)
> > � � � � � � � �return;
> >
> > - � � � r = &early_res[i];
> > � � � �/* hole ? */
> > � � � �if (r->end >= end && r->start <= start) {
> > � � � � � � � �drop_range_partial(i, start, end);
> > --
> > 1.7.1
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo(a)vger.kernel.org
> > More majordomo info at �http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at �http://www.tux.org/lkml/
> >
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