From: Valentin Schneider <valentin.schneider@xxxxxxx> commit b22a8f7b4bde4e4ab73b64908ffd5d90ecdcdbfd upstream. John Paul reported a warning about bogus NUMA distance values spurred by commit: 620a6dc40754 ("sched/topology: Make sched_init_numa() use a set for the deduplicating sort") In this case, the afflicted machine comes up with a reported 256 possible nodes, all of which are 0 distance away from one another. This was previously silently ignored, but is now caught by the aforementioned commit. The culprit is ia64's node_possible_map which remains unchanged from its initialization value of NODE_MASK_ALL. In John's case, the machine doesn't have any SRAT nor SLIT table, but AIUI the possible map remains untouched regardless of what ACPI tables end up being parsed. Thus, !online && possible nodes remain with a bogus distance of 0 (distances \in [0, 9] are "reserved and have no meaning" as per the ACPI spec). Follow x86 / drivers/base/arch_numa's example and set the possible map to the parsed map, which in this case seems to be the online map. Link: http://lore.kernel.org/r/255d6b5d-194e-eb0e-ecdd-97477a534441@xxxxxxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20210318130617.896309-1-valentin.schneider@xxxxxxx Fixes: 620a6dc40754 ("sched/topology: Make sched_init_numa() use a set for the deduplicating sort") Signed-off-by: Valentin Schneider <valentin.schneider@xxxxxxx> Reported-by: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx> Tested-by: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx> Tested-by: Sergei Trofimovich <slyfox@xxxxxxxxxx> Cc: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx> Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx> Cc: Anatoly Pugachev <matorola@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: dann frazier <dann.frazier@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/ia64/kernel/acpi.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/arch/ia64/kernel/acpi.c +++ b/arch/ia64/kernel/acpi.c @@ -448,7 +448,8 @@ void __init acpi_numa_fixup(void) if (srat_num_cpus == 0) { node_set_online(0); node_cpuid[0].phys_id = hard_smp_processor_id(); - return; + slit_distance(0, 0) = LOCAL_DISTANCE; + goto out; } /* @@ -491,7 +492,7 @@ void __init acpi_numa_fixup(void) for (j = 0; j < MAX_NUMNODES; j++) slit_distance(i, j) = i == j ? LOCAL_DISTANCE : REMOTE_DISTANCE; - return; + goto out; } memset(numa_slit, -1, sizeof(numa_slit)); @@ -516,6 +517,8 @@ void __init acpi_numa_fixup(void) printk("\n"); } #endif +out: + node_possible_map = node_online_map; } #endif /* CONFIG_ACPI_NUMA */ Patches currently in stable-queue which might be from valentin.schneider@xxxxxxx are queue-5.4/sched-topology-make-sched_init_numa-use-a-set-for-the-deduplicating-sort.patch queue-5.4/ia64-ensure-proper-numa-distance-and-possible-map-initialization.patch