Re: + workqueue-proper-error-unwinding-in-cpu-hotplug-error-path.patch added to -mm tree

[Oleg Nesterov <oleg@tv-sign.ru>]

On 07/22, Andrew Morton wrote:
> 
> From: Akinobu Mita <akinobu.mita@gmail.com>
> 
> Add proper error unwinding in error path in CPU_UP_PREPARE notifier.

Could you clarify?

> --- a/kernel/workqueue.c~workqueue-proper-error-unwinding-in-cpu-hotplug-error-path
> +++ a/kernel/workqueue.c
> @@ -928,6 +928,15 @@ static int __devinit workqueue_cpu_callb
>  				break;
>  			printk(KERN_ERR "workqueue [%s] for %i failed\n",
>  				wq->name, cpu);
> +
> +			list_for_each_entry_continue_reverse(wq, &workqueues,
> +							list) {
> +				cwq = per_cpu_ptr(wq->cpu_wq, cpu);
> +				start_workqueue_thread(cwq, -1);
> +				cleanup_workqueue_thread(cwq);
> +			}
> +			cpu_clear(cpu, cpu_populated_map);
> +
>  			return NOTIFY_BAD;

If CPU_UP_PREPARE fails, _cpu_up() sends CPU_UP_CANCELED, and afaics
workqueue_cpu_callback() correctly cleanups cwq->thread's.

Oleg.