powerpc/vphn: On Power systems with shared configurations of CPUs
and memory, there are some issues with the association of additional
CPUs and memory to nodes when hot-adding resources.  This patch
fixes an end-of-updates processing problem observed occasionally
in numa_update_cpu_topology().

Signed-off-by: Michael Bringmann <m...@linux.vnet.ibm.com>
---
 arch/powerpc/mm/numa.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 3a5b334..fccf23f 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1410,6 +1410,13 @@ int numa_update_cpu_topology(bool cpus_locked)
                cpu = cpu_last_thread_sibling(cpu);
        }
 
+       /*
+        * Prevent processing of 'updates' from overflowing array
+        * in cases where last entry filled in a 'next' pointer.
+        */
+       if (i)
+               updates[i-1].next = NULL;
+
        pr_debug("Topology update for the following CPUs:\n");
        if (cpumask_weight(&updated_cpus)) {
                for (ud = &updates[0]; ud; ud = ud->next) {

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