*** Lib/subprocess.py.bak	2015-09-13 01:25:34.542948040 +0200
--- Lib/subprocess.py	2015-09-13 01:32:39.019021311 +0200
*************** class Popen(object):
*** 679,684 ****
--- 679,685 ----
          self.stdout = None
          self.stderr = None
          self.pid = None
+         self.ppid = None
          self.returncode = None
          self.universal_newlines = universal_newlines
  
*************** class Popen(object):
*** 759,765 ****
              # We didn't get to successfully create a child process.
              return
          # In case the child hasn't been waited on, check if it's done.
!         self._internal_poll(_deadstate=_maxint)
          if self.returncode is None and _active is not None:
              # Child is still running, keep us alive until we can wait on it.
              _active.append(self)
--- 760,770 ----
              # We didn't get to successfully create a child process.
              return
          # In case the child hasn't been waited on, check if it's done.
!         try:
!             self._internal_poll(_deadstate=_maxint)
!         except OSError as e:
!             if e.errno != errno.ECHILD:
!                 raise
          if self.returncode is None and _active is not None:
              # Child is still running, keep us alive until we can wait on it.
              _active.append(self)
*************** class Popen(object):
*** 980,985 ****
--- 985,991 ----
              self._child_created = True
              self._handle = hp
              self.pid = pid
+             self.ppid = os.getpid()
              ht.Close()
  
          def _internal_poll(self, _deadstate=None,
*************** class Popen(object):
*** 1234,1239 ****
--- 1240,1246 ----
                              gc.enable()
                          raise
                      self._child_created = True
+                     self.ppid = os.getpid()
                      if self.pid == 0:
                          # Child
                          try:
*************** class Popen(object):
*** 1372,1377 ****
--- 1379,1392 ----
                          # disabled for our process.  This child is dead, we
                          # can't get the status.
                          # http://bugs.python.org/issue15756
+                         #
+                         # This also happens when the waiting process is not the
+                         # parent process -- we check for this here. Note that
+                         # this does not cover wait for pids in a spawned process
+                         # group -- so exclude waits on a negative pid (which
+                         # should never happen anyway)
+                         if (self.pid) > 0 and (self.ppid != os.getpid()):
+                             raise
                          self.returncode = 0
              return self.returncode
  
*************** class Popen(object):
*** 1388,1393 ****
--- 1403,1416 ----
                      # This happens if SIGCLD is set to be ignored or waiting
                      # for child processes has otherwise been disabled for our
                      # process.  This child is dead, we can't get the status.
+                     #
+                     # This also happens when the waiting process is not the
+                     # parent process -- we check for this here. Note that
+                     # this does not cover wait for pids in a spawned process
+                     # group -- so exclude waits on a negative pid (which
+                     # should never happen anyway)
+                     if (self.pid) > 0 and (self.ppid != os.getpid()):
+                         raise
                      pid = self.pid
                      sts = 0
                  # Check the pid and loop as waitpid has been known to return