Re: 2.4.0-test13-pre1 lockup: run_task_queue or tty_io are wrong

From: Linus Torvalds (torvalds@transmeta.com)
Date: Mon Dec 18 2000 - 18:58:08 EST


On Mon, 18 Dec 2000, Jamie Lokier wrote:
> >
> > Nope.
> >
> > There may be multiple concurrent run_task_queue's executing, so for now
> > I've applied Andrew Morton's patch that most closely gets the old
> > behaviour of having a private list.
>
> I wasn't clear. The sentinel is a local structure on the stack, and
> only exists while run_task_queue is executing. Another name for this is
> "deletion-safe pointer".

Yes, except run_task_queue removes every object it finds. So two
concurrent run_task_queues would be bad.

Sure, we could just make it skip sentinels by adding a magic flag to them,
but that is pretty ugly.

                Linus

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