From 8bc931495d4bfcde6bb242a478ddd1186ae29301 Mon Sep 17 00:00:00 2001
From: Michael Bringmann <mwb@linux.vnet.ibm.com>
Date: Fri, 8 Sep 2017 15:47:56 -0500
Subject: [PATCH] powerpc/vphn: Fix numa update end-loop bug
References: FATE#323745, bsc#1067906
Patch-mainline: v4.15-rc1
Git-commit: 8bc931495d4bfcde6bb242a478ddd1186ae29301
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 <mwb@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/mm/numa.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 32f5f8db46ec..ec098b3f7332 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1401,16 +1401,22 @@ int numa_update_cpu_topology(bool cpus_locked)
for_each_cpu(sibling, cpu_sibling_mask(cpu)) {
ud = &updates[i++];
+ ud->next = &updates[i];
ud->cpu = sibling;
ud->new_nid = new_nid;
ud->old_nid = numa_cpu_lookup_table[sibling];
cpumask_set_cpu(sibling, &updated_cpus);
- if (i < weight)
- ud->next = &updates[i];
}
cpu = cpu_last_thread_sibling(cpu);
}
+ /*
+ * Prevent processing of 'updates' from overflowing array
+ * 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) {
--
2.13.6