[PATCH 5.15 29/32] cpuset: Fix the bug that subpart_cpus updated wrongly in update_cpumask()

From: Greg Kroah-Hartman
Date: Fri Feb 04 2022 - 04:26:36 EST


From: Tianchen Ding <dtcccc@xxxxxxxxxxxxxxxxx>

commit c80d401c52a2d1baf2a5afeb06f0ffe678e56d23 upstream.

subparts_cpus should be limited as a subset of cpus_allowed, but it is
updated wrongly by using cpumask_andnot(). Use cpumask_and() instead to
fix it.

Fixes: ee8dde0cd2ce ("cpuset: Add new v2 cpuset.sched.partition flag")
Signed-off-by: Tianchen Ding <dtcccc@xxxxxxxxxxxxxxxxx>
Reviewed-by: Waiman Long <longman@xxxxxxxxxx>
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup/cpuset.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1597,8 +1597,7 @@ static int update_cpumask(struct cpuset
* Make sure that subparts_cpus is a subset of cpus_allowed.
*/
if (cs->nr_subparts_cpus) {
- cpumask_andnot(cs->subparts_cpus, cs->subparts_cpus,
- cs->cpus_allowed);
+ cpumask_and(cs->subparts_cpus, cs->subparts_cpus, cs->cpus_allowed);
cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
}
spin_unlock_irq(&callback_lock);