[bitbake-devel] [PATCH 1/1] bitbake: cooker: Kill alive process before join it

[Robert Yang]

Fixed:
$ echo helloworld >> meta/recipes-extended/bash/bash_4.4.18.bb
$ while true; do kill-bb; rm -fr bitbake-cookerdaemon.log tmp/cache/default-glibc/qemux86-64/x86_64/bb_cache.dat* ; bitbake -p; done

It may hang in 10 mins, there are two problems:
* There might be deadlocks when call process.join() if the queue is not NULL,
  so we need cleanup the queue before join() it, but:
* The self.result_queue.get(timeout=0.25) may hang if the queue._wlock is hold
  by SomeOtherProcess, the queue has the following info when it hangs:
  '_wlock': <Lock(owner=SomeOtherProcess)>, so that we may can't clean up the
  queue.

We can kill alvie process before join it to fix the problems.

Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
---
 bitbake/lib/bb/cooker.py | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/bitbake/lib/bb/cooker.py b/bitbake/lib/bb/cooker.py
index 0607fcc..e42bcba 100644
--- a/bitbake/lib/bb/cooker.py
+++ b/bitbake/lib/bb/cooker.py
@@ -2082,19 +2082,15 @@ class CookerParser(object):
             for process in self.processes:
                 self.parser_quit.put(None)
 
-        # Cleanup the queue before call process.join(), otherwise there might be
-        # deadlocks.
-        while True:
-            try:
-               self.result_queue.get(timeout=0.25)
-            except queue.Empty:
-                break
-
         for process in self.processes:
             if force:
                 process.join(.1)
                 process.terminate()
             else:
+                # Kill the alive process firstly before join() it to avoid
+                # deadlocks
+                if process.is_alive():
+                    os.kill(process.pid, 9)
                 process.join()
 
         sync = threading.Thread(target=self.bb_cache.sync)
-- 
2.7.4