[PATCH] sched/topology: Free NUMA masks on topology allocation failure

[Fengyu Wang]

sched_init_numa() publishes sched_domains_numa_masks before it
allocates the topology array.  When that allocation fails, the early
return leaves the masks published while sched_domains_numa_levels is
still zero: nothing dereferences them, but nothing can free them
either, and the topology they were built for is never installed.
Unpublish and free them instead.

Fixes: cb83b629bae0 ("sched/numa: Rewrite the CONFIG_NUMA sched domain support")
Signed-off-by: Fengyu Wang <wangfengyu@xxxxxxxx>
---
Tested by hardcoding tl to NULL right after the kzalloc() to force the
failure path; the masks are released and the machine boots normally.

 kernel/sched/topology.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 622e2e01974c..208fdc52f52d 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -2403,8 +2403,17 @@ void sched_init_numa(int offline_node)
 
 	tl = kzalloc((i + nr_levels + 1) *
 			sizeof(struct sched_domain_topology_level), GFP_KERNEL);
-	if (!tl)
+	if (!tl) {
+		rcu_assign_pointer(sched_domains_numa_masks, NULL);
+		synchronize_rcu();
+		for (i = 0; i < nr_levels; i++) {
+			for_each_node(j)
+				kfree(masks[i][j]);
+			kfree(masks[i]);
+		}
+		kfree(masks);
 		return;
+	}
 
 	/*
 	 * Copy the default topology bits..
-- 
2.34.1