Re: [Xenomai-help] Xenomai Bug: rt_intr_create with NULL-name leads to Kernel oops in /proc/xenomai/irq

[Jan Kiszka <jan.kiszka@domain.hid>]

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Dmitry Adamushko wrote:
>> > +     if (!err && name) {
>> > +             xnpnode_t *pnode = &__intr_pnode;
>> >
>> > -     if (!err)
>> > -             err =
>> > -                 xnregistry_enter(intr->name, intr, &intr->handle,
>> > -                                  &__intr_pnode);
>> > +             if (!*name) {
>> > +                     /* Since this is an anonymous object (empty
>> name on entry)
>>
>> Isn't a NULL name representing an anonymous object as well?
> 
> Anonymous objects are supported only for user-space clients.
> We agreed on it with Philippe when similar code was introduced for
> other objects. In this case, name is not NULL but "\0" on entry of
> native::rt_object_create (object = mutex,event,etc.).

OK, I see.

> 
> Now, don't ask me why the same is not applicable for the kernel-side
> objects as I'll have to think about it (can't recall right now) and
> may overheat. Likely, just some political issues. Yes, we want to make
> life of kernel-side developers a bit more difficult. Namely, want an
> object to be exported via registry? Give a valid name upon its
> creation.
> 
>> > -     xnintr_init(&intr->intr_base, name, irq, isr, iack, mode);
>> >       xnobject_copy_name(intr->name, name);
>> > +     xnintr_init(&intr->intr_base, intr->name, irq, isr, iack, mode);
>>
>> This will set xnintr_t::name to "" if name is NULL - intentionally?
> 
> xnintr_t::name becomes a reference to RT_INTR::name. The later one
> exists as long as the former anyway so there shoudn't be a broken
> reference.

Yes, this specifically addresses Mathias' concern about passed names
that are temporary variables.

It just leaves xnintr_t::name with an emptry string instead of "unknown"
in some cases. Either xnintr_init needs to take care of this, or we
should catch that case already here. I think empty strings in
/proc/xenomai/irq are bad in case of shared IRQ lists.

Jan


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