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    SubjectRe: route cache DoS testing and softirqs
    On Tue, Mar 30, 2004 at 10:36:14AM +0530, Srivatsa Vaddagiri wrote:
    > kthread_stop does:
    >
    > 1. kthread_stop_info.k = k;
    > 2. wake_up_process(k);
    >
    > and if ksoftirqd were to do :
    >
    > a. while (!kthread_should_stop()) {
    > b. __set_current_state(TASK_INTERRUPTIBLE);
    > c. schedule();
    > }
    >
    >
    > There is a (narrow) possibility here that a) happens _after_ 1) as well as
    > b) _after_ 2).

    hmm .. I meant a) happening _before_ 1) and b) happening _after_ 2) ..

    >
    > a. __set_current_state(TASK_INTERRUPTIBLE);
    > b. while (!kthread_should_stop()) {
    > c. schedule();
    > d. __set_current_state(TASK_INTERRUPTIBLE);
    > }
    >
    > e. __set_current_state(TASK_RUNNING);
    >
    > In this case, even if b) happens _after_ 1) and c) _after_ 2),

    Again I meant "even if b) happens _before_ 1) and c) _after_ 2) !!

    > schedule simply returns immediately because task's state would have been set
    > to TASK_RUNNING by 2). It goes back to the kthread_should_stop() check and
    > exits!

    --


    Thanks and Regards,
    Srivatsa Vaddagiri,
    Linux Technology Center,
    IBM Software Labs,
    Bangalore, INDIA - 560017
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