Re: [PATCH v9 06/12] kthread: Add kthread_drain_worker()

[Tejun Heo]

Hello,

On Wed, Jun 29, 2016 at 10:17:48AM +0200, Petr Mladek wrote:
> > Ah, okay, I don't think we need to change this.  I was suggesting to
> > simplify it by dropping the draining and just do flush from destroy.
> 
> I see. But then it does not address the original concern from Peter
> Zijlstra. He did not like that the caller was responsible for blocking
> further queueing. It still will be needed. Or did I miss something,
> please?

You can only protect against so much.  Let's say we make the worker
struct to be allocated by the user, what then prevents it prematurely
from user side?  Use-after-free is use-after-free.  If we can trivally
add some protection against it, great, but no need to contort the
design to add marginal protection.

Thanks.

-- 
tejun