bitbake: runqueue: Fix issues with multiconfig deferred task deadlock messages

In multiconfig builds with large numbers of identical tasks, builds were
deadlocking after recent runqueue changes upon rebuilds where there was
heavy sstate usage (i.e. on second builds after a first completed).

The issue was that deferred tasks were being left indefinitely on
the deferred list. The deadlock handler was then "breaking" things
by failing tasks that had already succeeded, leading to the task
being on both covered and not covered lists, giving a further error.

The fix is to clean up the deferred task list when each setscene task
completes. I'd previously been hoping to avoid iterating that list
but it appears unavoidable.

[YOCTO #14342]

(Bitbake rev: ae24a0f2d2d8b4b5ec10efabd0e9362e560832ea)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/runqueue.py

@@ -1904,6 +1904,12 @@ class RunQueueExecute:
                 self.setbuildable(revdep)
                 logger.debug("Marking task %s as buildable", revdep)
 
+        for t in self.sq_deferred.copy():
+            if self.sq_deferred[t] == task:
+                logger.debug2("Deferred task %s now buildable" % t)
+                del self.sq_deferred[t]
+                update_scenequeue_data([t], self.sqdata, self.rqdata, self.rq, self.cooker, self.stampcache, self, summary=False)
+
     def task_complete(self, task):
         self.stats.taskCompleted()
         bb.event.fire(runQueueTaskCompleted(task, self.stats, self.rq), self.cfgData)