Messages in this thread | | | Subject | Re: [PATCH] arm64/numa: Add more vetting in numa_set_distance() | From | John Garry <> | Date | Mon, 29 Oct 2018 12:14:09 +0000 |
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On 29/10/2018 11:25, Will Deacon wrote: > Hi John, >
Hi Will,
> 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 <john.garry@huawei.com> >> >> 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().
Right, I did notice this. I didn't think that x86 folks would be so concerned since they generally only use ACPI, and the ACPI code already validates these distances in drivers/acpi/numa.c: slit_valid() [unlike OF code].
I think we should either factor out the sanity check > into a core helper or make the core code robust to these funny configurations.
OK, so to me it would make sense to factor out a sanity check into a core helper.
Cheers, John
> > Will > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > >
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