Suspending Tasks before they are finished

[Joel Sherrill]

On Mon, Mar 14, 2022 at 6:44 AM Jerzy J <yuralogplus at gmail.com> wrote:

> Hi,
>
> I've been developing some tests and observed some task behaviour that i
> can't understand and couldn't find any documentation about it.
>
> I have tests where I create 2 extra tasks (Workers) and then those tasks
> are blocked and unlocked using semaphores and barriers. However, whenever
> main task (Runner) is about to get blocked, the test crashes (just finishes
> instantly). In some configurations is seems to "deadlock" on a semaphore
> instead, while it should be able to move forward.
>
> I realised that if I suspend the Worker tasks before they are about to
> finish, with for e.g:
> `rtems_event_receive( RTEMS_ALL_EVENTS, RTEMS_DEFAULT_OPTIONS, 0, &events
> );`
> line at the very end of worker execution, it all works as expected.
>

If these are Classic API tasks (e.g. rtems_task_create) and they are
falling off
the bottom of the function that is the task body, that's a fatal error. If
it is a POSIX
thread, it silently goes away.

>
> Do you maybe know what is the reason for such behaviour? I'm also not sure
> in which state is the task after it finishes it's execution but before it
> is deleted, is it 'blocked' or is it 'dormant'?
>

Depends on the API and attributes on a pthread.

--joel

>
> Thanks and all the best,
> Jerzy
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