bitbake: event: Fix an event duplication race

It is possible for multple bitbake threads to empty ui_queue in parallel
leading to duplicate console messages and much confusion when debuging.

Use the lock to extract the queue data which means only one thread will
processing, removing the duplicate out of order messages.

(Bitbake rev: 945095602e40d54efb8de494218f4a2b25c9969f)

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

1 files changed, 5 insertions, 2 deletions

diff --git a/bitbake/lib/bb/event.py b/bitbake/lib/bb/event.py
index b29f0a5568..2256fed764 100644
--- a/bitbake/lib/bb/event.py
+++ b/bitbake/lib/bb/event.py
@@ -236,9 +236,12 @@ def fire(event, d):
         # If messages have been queued up, clear the queue
         global _uiready, ui_queue
         if _uiready and ui_queue:
-            for queue_event in ui_queue:
+            with bb.utils.lock_timeout_nocheck(_thread_lock):
+                queue = ui_queue
+                ui_queue = []
+            for queue_event in queue:
                 fire_ui_handlers(queue_event, d)
-            ui_queue = []
+
         fire_ui_handlers(event, d)
 
 def fire_from_worker(event, d):