From: Waiman Long longman@redhat.com
[ Upstream commit 15d428e6fe77fffc3f4fff923336036f5496ef17 ]
In cpuset_hotplug_workfn(), the detection of whether the cpu list has been changed is done by comparing the effective cpus of the top cpuset with the cpu_active_mask. However, in the rare case that just all the CPUs in the subparts_cpus are offlined, the detection fails and the partition states are not updated correctly. Fix it by forcing the cpus_updated flag to true in this particular case.
Fixes: 4b842da276a8 ("cpuset: Make CPU hotplug work with partition") Signed-off-by: Waiman Long longman@redhat.com Signed-off-by: Tejun Heo tj@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/cgroup/cpuset.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index adb5190c4429..592e9e37542f 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3168,6 +3168,13 @@ static void cpuset_hotplug_workfn(struct work_struct *work) cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus); mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
+ /* + * In the rare case that hotplug removes all the cpus in subparts_cpus, + * we assumed that cpus are updated. + */ + if (!cpus_updated && top_cpuset.nr_subparts_cpus) + cpus_updated = true; + /* synchronize cpus_allowed to cpu_active_mask */ if (cpus_updated) { spin_lock_irq(&callback_lock);