[LITMUS^RT] possible inheritance/boosting conflict

[Björn Brandenburg]

On 09 Apr 2014, at 19:25, Glenn Elliott <gelliott at cs.unc.edu> wrote:

> I was reviewing the code in edf_higher_prio(), and I think that I may have stumbled across a bug.  I don’t believe that we’ve actually ever hit this bug before because it requires a task to both inherit a priority and itself be boosted. 

Indeed, we currently have no protocol that would require priority inheritance and boosting at the same time. I'm also not immediately aware of one in the literature that would require this. So edf_higher_prio() doesn't handle that case.

> Nevertheless, I think edf_higher_prio() should be robust enough to handle such a case.

Mh, I don't know. If you need it for ongoing development, sure. But I don't necessarily agree that "generality of the sake of generality" is needed here. If the current, simple version is good enough for what's required by the current implementation, why fix it?

> Is this a bug?  I think one can argue that Task A should not have inherited from Task T if Task A was already boosted when inheritance was established, or the inheritance should have been terminated when Task A was boosted after inheritance was established.

Do you have a specific case where we need boosting and inheritance at the same time? I think such a case might inform the best way to handle this combination.

Thanks,
Björn