Re: next: WARNING: CPU: 0 PID: 63 at kernel/workqueue.c:1999 worker_enter_idle+0xb2/0xc0

Hello,

On Mon, May 22, 2023 at 09:24:09PM +0800, Z qiang wrote:

diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 9c5c1cfa478f..f8d739fef311 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1060,10 +1060,9 @@ void wq_worker_running(struct task_struct *task) * and leave with an unexpected pool->nr_running == 1 on the newly unbound * pool. Protect against such race. */

•   preempt_disable();
  

•   local_irq_disable();
    if (!(worker->flags & WORKER_NOT_RUNNING))
            worker->pool->nr_running++;
  

•   preempt_enable();
  
    /*
     * CPU intensive auto-detection cares about how long a work item
  

hogged @@ -1072,6 +1071,7 @@ void wq_worker_running(struct task_struct *task) worker->current_at = worker->task->se.sum_exec_runtime;

    worker->sleeping = 0;

•   local_irq_enable();
  

}

Ah, yeah, this is correct. Now we're modifying nr_running from timer tick too, so if don't block irq, the timer tick can ruin the not-irq-protected read-write-modify nr_running update from wq_worker_running(). Naresh, can you please confirm the fix?

Thanks.