Re: cgroup_enable_task_cg_lists && PF_EXITING (Was: KCSAN: data-race in exit_signals / prepare_signal)

[Tejun Heo]

Hello, Oleg.

On Mon, Oct 21, 2019 at 04:21:11PM +0200, Oleg Nesterov wrote:
> could you explain the usage of siglock/PF_EXITING in
> cgroup_enable_task_cg_lists() ?
> 
> PF_EXITING is protected by cgroup_threadgroup_rwsem, not by
> sighand->siglock.

Yeah, the optimization was added a really long time ago and I'm not
sure it was ever correct.  I'm removing it.  If this ever becomes a
problem (pretty unlikely), I think the right thing to do is adding a
boot param instead of trying to do this dynamically.

Thanks.

-- 
tejun