On Mon, Sep 02, 2019 at 11:52:01PM -0500, Eric W. Biederman wrote: > > In the ordinary case today the rcu grace period of a task comes when a > task is reaped, well after the task has left the runqueue. This > change guarantees that the rcu grace period always happens after a > task has left the runqueue. As this is something that usaually happens > today I do not expect any code correctness problems with this change. > At most I anticipate timing challenges.
What do you consider as the reaping point here? If this is the call to release_task(), it can happen way before the task forever leaves the runqueue. Let alone the RCU call to delayed_put_task_struct() can happen way before the target leaves the runqueue, either after autoreap or normal reaping.