On Mon, Sep 12, 2011 at 3:47 PM, Gaurav Mahajan <gauravmahajan2007@gmail.com> wrote:

Hi,

I have a douby regarding  kthread working.

How can we check that a kthread is working or exited. It  may exit beacuse of call to do_exit in threadfn or callling kthread_stop function on task_struct (correct me if i am weong).

I want to check that if kthread has finished its work or not. If not then what should I call so that kthread gets killed. If it is finshhed then which function I should call so that as to free kthread resources.

Regards, Gaurav Mahajan.

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kthread_stop function should itself block untill thread gets killed. However if thread is already killed, its task_struct won't be valid. If its your thread, it should be fairly possible for you keep keep single exit point, i.e. notify this thread to stop using 'kthread_stop'. However if you are upto hacking some kernel thread, kthread_stop() may not work on already exited task, as there won't be any way to identify a killed thread. Probably you should avoid such design choices. -Rajat