Reading about SCHED_RR, we had some reports in focal which were about issues setting real-time priority to processes and that appeared to be caused by enabling CONFIG_RT_GROUP_SCHED (which was a request by docker). That happened before release and after 5.4.0-21 (see bug #1873315). And Thadeu's commment #6 points to code which is active only when that config is turned on.
So this is something that we released with and the question is whether it should be "fixed" by turning this off again or having properly handled the special cases.
Reading about SCHED_RR, we had some reports in focal which were about issues setting real-time priority to processes and that appeared to be caused by enabling CONFIG_ RT_GROUP_ SCHED (which was a request by docker). That happened before release and after 5.4.0-21 (see bug #1873315). And Thadeu's commment #6 points to code which is active only when that config is turned on.
So this is something that we released with and the question is whether it should be "fixed" by turning this off again or having properly handled the special cases.