1 files changed, 13 insertions, 1 deletions

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index df77c605c7a6..c11e36ff5ea0 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1201,9 +1201,21 @@ static int task_numa_migrate(struct task_struct *p)
          */
         rcu_read_lock();
         sd = rcu_dereference(per_cpu(sd_numa, env.src_cpu));
-        env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2;
+        if (sd)
+                env.imbalance_pct = 100 + (sd->imbalance_pct - 100) / 2;
         rcu_read_unlock();
 
+        /*
+         * Cpusets can break the scheduler domain tree into smaller
+         * balance domains, some of which do not cross NUMA boundaries.
+         * Tasks that are "trapped" in such domains cannot be migrated
+         * elsewhere, so there is no point in (re)trying.
+         */
+        if (unlikely(!sd)) {
+                p->numa_preferred_nid = cpu_to_node(task_cpu(p));
+                return -EINVAL;
+        }
+
         taskweight = task_weight(p, env.src_nid);
         groupweight = group_weight(p, env.src_nid);
         update_numa_stats(&env.src_stats, env.src_nid);