Hi John, On Fri, Oct 26, 2018 at 09:57:47PM +0800, John Garry wrote: > Currently it is acceptable to set the distance between 2 separate nodes to > LOCAL_DISTANCE. > > Reject this as it is invalid. > > This change avoids a crash reported in [1]. > > [1] https://www.spinics.net/lists/arm-kernel/msg683304.html > > Signed-off-by: John Garry <[email protected]> > > diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c > index 146c04c..6092e3d 100644 > --- a/arch/arm64/mm/numa.c > +++ b/arch/arm64/mm/numa.c > @@ -335,7 +335,8 @@ void __init numa_set_distance(int from, int to, int > distance) > } > > if ((u8)distance != distance || > - (from == to && distance != LOCAL_DISTANCE)) { > + (from == to && distance != LOCAL_DISTANCE) || > + (from != to && distance == LOCAL_DISTANCE)) {
The current code here is more-or-less lifted from the x86 implementation of numa_set_distance(). I think we should either factor out the sanity check into a core helper or make the core code robust to these funny configurations. Will
