Re: [PATCH] sched: Avoid that __wait_on_bit_lock() hangs

[Peter Zijlstra]

On Fri, Aug 05, 2016 at 10:41:33AM -0700, Bart Van Assche wrote:
> On 08/04/2016 07:09 AM, Peter Zijlstra wrote:

> >But I'd still like to understand where we loose the wakeup.
> 
> My assumption is that __wake_up_common() and signal delivery happen
> concurrently, that __wake_up_common() wakes up bit_wait_io() and that signal
> delivery happens after bit_wait_io() has been woken up but before it tests
> the signal pending state.

That would be the exact scenario I drew a picture of, no? I'm still
failing to see the hole there.

Please draw a picture like that and illustrate the hole.