early_res: fix check in free_early_partial
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From: Yinghai Lu on 4 Jun 2010 20:10 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 > -- > 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/ > -- 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/
From: Adam Lackorzynski on 6 Jun 2010 07:40
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/ > > -- 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/ |