Re: [PATCH v7 16/22] sched: Defer wakeup in ttwu() for unschedulable frozen tasks

From: Peter Zijlstra
Date: Thu May 27 2021 - 10:55:50 EST

On Thu, May 27, 2021 at 03:44:12PM +0100, Will Deacon wrote:
> I'm not seeing how this handles tasks which weren't put in the freezer
> because they have PF_FREEZER_SKIP set. For these tasks, we need to make
> sure that they don't become runnable before we have onlined a core which
> is capable of running them, and this could occur because of any old
> wakeup (i.e. whatever it was that they blocked on).

I was under the impression that userspace tasks could not have
PF_FREEZER_SKIP set.. let me look harder.