sched-urgent-2020-07-19

 - Plug a load average accounting race which was introduced with a recent
   optimization casing load average to show bogus numbers.

 - Fix the rseq CPU id initialization for new tasks. sched_fork() does not
   update the rseq CPU id so the id is the stale id of the parent task,
   which can cause user space data corruption.

 - Handle a 0 return value of task_h_load() correctly in the load balancer,
   which does not decrease imbalance and therefore pulls until the maximum
   number of loops is reached, which might be all tasks just created by a
   fork bomb.