Re: [PATCH cgroup/for-5.5] cgroup: remove cgroup_enable_task_cg_lists() optimization

[Oleg Nesterov]

On 10/25, Christian Brauner wrote:
>
> On Fri, Oct 25, 2019 at 04:13:25PM +0200, Oleg Nesterov wrote:
> > Almost every usage of task->flags (load or sore) can be reported as "data race".
> > 
> > Say, you do
> > 
> > 	if (task->flags & PF_KTHREAD)
> > 
> > while this task does
> > 
> > 	current->flags |= PF_FREEZER_SKIP;
> > 	schedule().
> > 
> > this is data race.
> 
> Right, but I thought we agreed on WONTFIX in those scenarios?
> The alternative is to READ_ONCE()/WRITE_ONCE() all of these.

Well, in my opinion this is WONTFIX, but I won't argue if someone
adds _ONCE to all of these. Same for task->state, exit_state, and
more.

Oleg.