Re: [PATCH 09/10] kthread: Ensure struct kthread is present for all kthreads

[Al Viro]

On Wed, Dec 08, 2021 at 02:25:31PM -0600, Eric W. Biederman wrote:
> Today the rules are a bit iffy and arbitrary about which kernel
> threads have struct kthread present.  Both idle threads and thread
> started with create_kthread want struct kthread present so that is
> effectively all kernel threads.  Make the rule that if PF_KTHREAD
> and the task is running then struct kthread is present.
> 
> This will allow the kernel thread code to using tsk->exit_code
> with different semantics from ordinary processes.

Getting rid of ->exit_code abuse is independent from this.
I'm not saying that this change is a bad idea, but it's an
independent thing.  Simply turn these two failure exits
into do_exit(0) in 06/10 and that's it.  Then this one
would get rid of if (!self) and the second of those two
calls, but it won't be nailed to that point of queue.