Re: [PATCH] kthread: Enhance kthread_stop to abort interruptible sleeps

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

On 04/24, Oleg Nesterov wrote:
>
> Hm, mm_release() clears ->vfork_done before complete().
> 
> 	mm_release:
> 
> 		struct completion *vfork_done = tsk->vfork_done;
> 
> 		if (vfork_done) {
> 			tsk->vfork_done = NULL;
> 			complete(vfork_done);
> 		}
> 
> 
> 	kthread_stop:
> 
> 		set_tsk_thread_flag(tsk, TIF_KTHREAD_STOP);
> 		signal_wake_up(tsk, 1);
> 
> 		// tsk exits, sets ->vfork_done == NULL
> 
> 		wait_for_completion(tsk->vfork_done);

Since the task_struct should be pinned anyway, I think kthread_stop()
should do:

	vfork_done = tsk->vfork_done;
	barrier();
	if (vfork_done)
		wait_for_completion(vfork_done);

Oleg.

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