tor/changes/bug23676

  o Major bugfixes (scheduler):
    If a channel is put into the scheduler's pending list, then it starts
    closing, and then if the scheduler runs before it finishes closing, the
    scheduler will get stuck trying to flush its cells while the lower layers
    refuse to cooperate. Fix that race condition by given the scheduler an
    escape method. Fixes bug 23676; bugfix on 0.3.2.1-alpha
sched: Don't get KIST stuck in an infinite loop When a channel is scheduled and flush cells returns 0 that is no cells to flush, we flag it back in waiting for cells so it doesn't get stuck in a possible infinite loop. It has been observed on moria1 where a closed channel end up in the scheduler where the flush process returned 0 cells but it was ultimately kept in the scheduling loop forever. We suspect that this is due to a more deeper problem in tor where the channel_more_to_flush() is actually looking at the wrong queue and was returning 1 for an empty channel thus putting the channel in the "Case 4" of the scheduler which is to go back in pending state thus re-considered at the next iteration. This is a fix that allows the KIST scheduler to recover properly from a not entirelly diagnosed problem in tor. Fixes #23676 Signed-off-by: David Goulet <dgoulet@torproject.org> 2017-09-27 22:11:05 +02:00			`o Major bugfixes (scheduler):`
			`If a channel is put into the scheduler's pending list, then it starts`
			`closing, and then if the scheduler runs before it finishes closing, the`
			`scheduler will get stuck trying to flush its cells while the lower layers`
			`refuse to cooperate. Fix that race condition by given the scheduler an`
			`escape method. Fixes bug 23676; bugfix on 0.3.2.1-alpha`