bitbake: server/process: Disable gc around critical section

The python gc can trigger whilst we're holding the event stream lock
and when cleaning up objects, they can trigger warnings. This translates
into a new event which would then need the lock and we can deadlock.

Disable gc whilst we hold that lock to avoid this unfortunate and
problematic situation.

(Bitbake rev: 0784db7dd0fef6f0621ad8d74372f44e87fef950)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 96a6303949cefd469bcf5ed250ff512271354357)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/server/process.py

@@ -25,6 +25,7 @@ import subprocess
 import errno
 import re
 import datetime
+import gc
 import bb.server.xmlrpcserver
 from bb import daemonize
 from multiprocessing import queues
@@ -671,8 +672,10 @@ class ConnectionWriter(object):
 
     def send(self, obj):
         obj = multiprocessing.reduction.ForkingPickler.dumps(obj)
+        gc.disable()
         with self.wlock:
             self.writer.send_bytes(obj)
+        gc.enable()
 
     def fileno(self):
         return self.writer.fileno()