How can I terminate a thread that is in a waiting state?

RE: How can I terminate a thread that is in a waiting state?

Andrea Verdecchia — Thu, 16 Jan 2025 09:36:47 GMT

Thank you for clarifying

RE: How can I terminate a thread that is in a waiting state?

Susheel Nuguru — Thu, 16 Jan 2025 09:11:31 GMT

You are right Andrea, the else if statement takes care of that. So flag seems to be a good choice ...

RE: How can I terminate a thread that is in a waiting state?

Andrea Verdecchia — Wed, 15 Jan 2025 18:54:44 GMT

[quote userid="6207" url="~/f/nordic-q-a/118048/how-can-i-terminate-a-thread-that-is-in-a-waiting-state/518505"]getting a fifo item within 100 milliseconds else this thread will be killed[/quote]

Why do you say that if I don't receive a FIFO object, the process gets killed? In my last example, if the timeout expires, the FIFO object will be NULL, and in that case, if the variable terminate_thread_flag has been set, then I terminate the process with a return. Otherwise, I restart the for loop.

RE: How can I terminate a thread that is in a waiting state?

Susheel Nuguru — Wed, 15 Jan 2025 17:35:57 GMT

The concern with using timeout in fifo_get is that you count on getting a fifo item within 100 milliseconds else this thread will be killed. If that fits your design, that a delay of 100ms in getting a fifo item means you wont get it anymore then the above code looks right. Else I would use abort.

RE: How can I terminate a thread that is in a waiting state?

Andrea Verdecchia — Wed, 15 Jan 2025 16:44:24 GMT

The type of thread I used as an example remains indefinitely waiting for incoming data (in this case, via a FIFO). To terminate such a thread that is waiting for data that will no longer arrive, is it preferable to use a timeout like this:

void Foo_Thread(void) {
    fifo_ble_communication_item_t *fifoItem;

    for (;;) {
        fifoItem = k_fifo_get(&fooFifo, K_MSEC(100));
        
        if (fifoItem != NULL) {
            /* use fifoItem data */
        } else if (terminate_thread_flag == true) {
            return;
        }
    }
}

Or k_thread_abort() without the timeout?

RE: How can I terminate a thread that is in a waiting state?

Susheel Nuguru — Wed, 15 Jan 2025 15:50:21 GMT

Hmm,

Something is not right,

[quote user=""]But how can I terminate a thread that is in a waiting state with K_FOREVER and that I know will never unblock[/quote]

A thread that have reached to this point seems like a mistake and should have aborted if it went into that state knowingly. If that thread went into this state due to unhandled conditions, and another thread can detect this, then there are many ways to do this. Use flags or timeouts

For example using a flag like terminate_thread_flag

static volatile bool terminate_thread_flag = false;

void main(void)
{
    k_tid_t thread_id = k_thread_create(..., Foo_Thread, ...);

    // wome work
    xxx_xxx

    // Notify the thread to terminate
    terminate_thread_flag = true;


}

and the thread that needs killing can have the flag checked in the start like below

void Foo_Thread(void)
{
    struct fifo_item *fifoItem;

    while (!terminate_thread_flag) {
    ...
    ...