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From:   Tianchen Ding <dtcccc@linux.alibaba.com>
To:     Zefan Li <lizefan.x@bytedance.com>, Tejun Heo <tj@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Waiman Long <longman@redhat.com>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc:     cgroups@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] cpuset: Fix the bug that subpart_cpus updated wrongly in update_cpumask()
Date:   Tue, 18 Jan 2022 18:05:18 +0800
Message-Id: <20220118100518.2381118-1-dtcccc@linux.alibaba.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@linux.alibaba.com>
---
 kernel/cgroup/cpuset.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index bb3531e7fda7..804ff5738c5f 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1635,8 +1635,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
 	 * 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);
-- 
2.33.0