sched: fix new task startup crash (b9dca1e0) · Commits · 戴 / test

Child task may be added on a different cpu that the one on which parent is running. In which case, task_new_fair() should check whether the new born task's parent entity should be added as well on the cfs_rq. Patch below fixes the problem in task_new_fair. This could fix the put_prev_task_fair() crashes reported. Reported-by:

Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Reported-by:

Andy Whitcroft <apw@shadowen.org> Signed-off-by:

Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

kernel/sched.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1712,7 +1712,7 @@ void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)

		p->prio = effective_prio(p);

		if (!p->sched_class->task_new \|\| !current->se.on_rq \|\| !rq->cfs.curr) {
		if (!p->sched_class->task_new \|\| !current->se.on_rq) {
		activate_task(rq, p, 0);
		} else {
		/*

kernel/sched_fair.c

+1 −5

Original line number	Diff line number	Diff line
		@@ -1031,12 +1031,8 @@ static void task_new_fair(struct rq rq, struct task_struct p)
		swap(curr->vruntime, se->vruntime);
		}

		update_stats_enqueue(cfs_rq, se);
		check_spread(cfs_rq, se);
		check_spread(cfs_rq, curr);
		__enqueue_entity(cfs_rq, se);
		account_entity_enqueue(cfs_rq, se);
		se->peer_preempt = 0;
		enqueue_task_fair(rq, p, 0);
		resched_task(rq->curr);
		}

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