[Python-checkins] cpython: Try to print a backtrace of wedged child process in test.

[richard.oudkerk]

http://hg.python.org/cpython/rev/6f4806323208
changeset:   86391:6f4806323208
user:        Richard Oudkerk <shibturn at gmail.com>
date:        Thu Oct 17 10:38:37 2013 +0100
summary:
  Try to print a backtrace of wedged child process in test.

files:
  Lib/test/_test_multiprocessing.py |  13 +++++++++++++
  1 files changed, 13 insertions(+), 0 deletions(-)


diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -300,6 +300,9 @@
         p.terminate()
 
         if hasattr(signal, 'alarm'):
+            # On the Gentoo buildbot waitpid() often seems to block forever.
+            # We use alarm() to interrupt it if it blocks for too long, and
+            # then try to print a backtrace for the child process using gdb.
             def handler(*args):
                 raise RuntimeError('join took too long: %s' % p)
             old_handler = signal.signal(signal.SIGALRM, handler)
@@ -307,6 +310,16 @@
                 signal.alarm(10)
                 self.assertEqual(join(), None)
                 signal.alarm(0)
+            except RuntimeError:
+                print('os.waitpid() =', os.waitpid(p.pid, os.WNOHANG))
+                import subprocess
+                p = subprocess.Popen(['gdb', sys.executable, str(p.pid)],
+                                     stdin=subprocess.PIPE)
+                try:
+                    p.communicate(b'bt 50', timeout=10)
+                except subprocess.TimeoutExpired:
+                    p.kill()
+                raise
             finally:
                 signal.signal(signal.SIGALRM, old_handler)
         else:

-- 
Repository URL: http://hg.python.org/cpython