Fatal exceptions on context-switching for more than two isolated threads

[Gedare Bloom]

Hi Utkarsh,

On Thu, Nov 19, 2020 at 4:59 AM Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
>
> On 19/11/2020 11:47, Utkarsh Rai wrote:
>
> >     There are a couple of other areas in RTEMS in which the stack of
> >     another
> >     thread may be accessed (events, message queues, signals). How did you
> >     solve this?
> >
> >
> > When we enable the thread stack protection, all the services in which
> > a different stack is accessed becomes invalid ( This will have to be
> > documented  ).
> > The user has to share the stack of the threads that will be using
> > services like message queue with each other from the application using
> > mmap(),shm_open(), etc. (This was a part of the work I did during GSoC).
>
> This is a bit too restrictive from my point of view. Consider for
> example this very common use of rtems_event_receive():
>
> rtems_event_set events;
>
> rtems_event_receive(..., &events, ...);
>
Let's try to keep the technical discussion on the mailing list. I
agree with Sebastian's point here, which is well taken. Maybe it would
be good for you to determine the set of tests and from that the
features that break with strict task isolation. This way, we can
determine whether each is better handled as imposing a requirement on
the user, e.g., to mmap/share explicitly in case they want to pass
data (such as with an mq), or if RTEMS needs to make it work
implicitly such as with event sets and maybe these iterators.

Gedare

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