Messages in this thread Patch in this message | | | From | Lai Jiangshan <> | Subject | [PATCH] workqueue: Avoid a false warning in unbind_workers() | Date | Fri, 29 Jul 2022 17:44:38 +0800 |
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From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Doing set_cpus_allowed_ptr() with wq_unbound_cpumask can be possible fails and trigger the false warning.
Use cpu_possible_mask instead when wq_unbound_cpumask has no active CPUs.
It is very easy to trigger the warning: Set wq_unbound_cpumask to a small set of CPUs. Offline all the CPUs of wq_unbound_cpumask. Offline an extra CPU and trigger the warning.
Fixes: 10a5a651e3af("workqueue: Restrict kworker in the offline CPU pool running on housekeeping CPUs") Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com> --- kernel/workqueue.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 355897b790a5..a429b50b06e6 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -4975,7 +4975,10 @@ static void unbind_workers(int cpu) for_each_pool_worker(worker, pool) { kthread_set_per_cpu(worker->task, -1); - WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, wq_unbound_cpumask) < 0); + if (cpumask_intersects(wq_unbound_cpumask, cpu_active_mask)) + WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, wq_unbound_cpumask) < 0); + else + WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, cpu_possible_mask) < 0); } mutex_unlock(&wq_pool_attach_mutex); -- 2.19.1.6.gb485710b
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