Re: [PATCH] sched/deadline/rtmutex: Fix a PI crash for deadline tasks

[Xunlei Pang]

On 2016/04/12 at 23:51, Peter Zijlstra wrote:
> On Tue, Apr 12, 2016 at 11:08:04AM +0800, Xunlei Pang wrote:
>> I spotted another issue, we access pi_task without any lock in enqueue_task_dl(),
> OK, so I'm on the road and entirely jetlagged, but how can
> enqueue_task_dl() not have rq->lock held?

It held current's rq->lock, but not holding pi_task's any lock, so pi_task's attributes
can change concurrently with subsequent pi_se->dl_runtime and pi_se->dl_period
access, and result in issues.

Regards,
Xunlei