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

[Utkarsh Rai]

On Thu, Nov 19, 2020 at 11:39 PM Gedare Bloom <gedare at rtems.org> wrote:

> 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.


Oh sorry, I somehow forgot to cc 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
>


Ok.


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