It happens that the fix relies on checking if the stop worker needs task selection re-start:
+ if (need_pull_dl_task(rq, prev)) { pull_dl_task(rq); + /* + * pull_rt_task() can drop (and re-acquire) rq->lock; this + * means a stop task can slip in, in which case we need to + * re-start task selection. + */ + if (rq->stop && rq->stop->on_rq) + return RETRY_TASK; And this is done by returning RETRY_TASK. This logic was not available in 3.13 AND I don't want to jeopardise our 3.13 scheduler. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1461620 Title: NUMA task migration race condition due to stop task not being checked when balancing happens To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1461620/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs