[PATCH-next v4 4/9] cgroup/cpuset: Do housekeeping check before converting invalid partition to valid

[Waiman Long]

When a hotplug event happens or when update_cpumasks_hier() is called, an
invalid partition may be converted back to valid. However check against
housekeeping conflict isn't being done which can lead to a partition
state that violates the housekeeping rules. Update the code to allow
reviving an invalid partition only if it can pass the housekeeping check.

Fixes: 4a74e418881f ("cgroup/cpuset: Check partition conflict with housekeeping setup")
Reviewed-by: Guopeng Zhang <zhangguopeng@xxxxxxxxxx>
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
 kernel/cgroup/cpuset.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index cef3cd0a6906..046c7ce5a037 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1981,9 +1981,15 @@ static int update_parent_effective_cpumask(struct cpuset *cs, int cmd,
 			bool exclusive = true;
 
 			/*
-			 * Convert invalid partition to valid has to
-			 * pass the cpu exclusivity test.
+			 * Convert invalid partition to valid has to pass the
+			 * cpu exclusivity test as well as the housekeeping
+			 * check.
 			 */
+			if (prstate_housekeeping_conflict(cs->partition_root_state,
+							  parent_prs, xcpus, NULL)) {
+				part_error = PERR_HKEEPING;
+				goto write_error;
+			}
 			rcu_read_lock();
 			cpuset_for_each_child(child, css, parent) {
 				if (child == cs)
-- 
2.55.0