Issue #12650: Fix a race condition where a subprocess.Popen could leak
resources (FD/zombie) when killed at the wrong time.
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index ec417c2..db64588 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -424,12 +424,16 @@
except:
MAXFD = 256
+# This lists holds Popen instances for which the underlying process had not
+# exited at the time its __del__ method got called: those processes are wait()ed
+# for synchronously from _cleanup() when a new Popen object is created, to avoid
+# zombie processes.
_active = []
def _cleanup():
for inst in _active[:]:
res = inst._internal_poll(_deadstate=sys.maxsize)
- if res is not None and res >= 0:
+ if res is not None:
try:
_active.remove(inst)
except ValueError:
@@ -1272,6 +1276,7 @@
errread, errwrite,
errpipe_read, errpipe_write,
restore_signals, start_new_session, preexec_fn)
+ self._child_created = True
finally:
# be sure the FD is closed no matter what
os.close(errpipe_write)