diff --git a/Lib/multiprocessing/shared_memory.py b/Lib/multiprocessing/shared_memory.py index a3a5fcf4aba1e7..122b3fcebf3fed 100644 --- a/Lib/multiprocessing/shared_memory.py +++ b/Lib/multiprocessing/shared_memory.py @@ -76,6 +76,8 @@ def __init__(self, name=None, create=False, size=0): raise ValueError("'size' must be a positive integer") if create: self._flags = _O_CREX | os.O_RDWR + if size == 0: + raise ValueError("'size' must be a positive number different from zero") if name is None and not self._flags & os.O_EXCL: raise ValueError("'name' can only be None if create=True") diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py index c783fc2402195c..e47905c863bafa 100644 --- a/Lib/test/_test_multiprocessing.py +++ b/Lib/test/_test_multiprocessing.py @@ -3864,6 +3864,18 @@ class OptionalAttachSharedMemory(shared_memory.SharedMemory): sms.close() + # Test creating a shared memory segment with negative size + with self.assertRaises(ValueError): + sms_invalid = shared_memory.SharedMemory(create=True, size=-1) + + # Test creating a shared memory segment with size 0 + with self.assertRaises(ValueError): + sms_invalid = shared_memory.SharedMemory(create=True, size=0) + + # Test creating a shared memory segment without size argument + with self.assertRaises(ValueError): + sms_invalid = shared_memory.SharedMemory(create=True) + def test_shared_memory_across_processes(self): # bpo-40135: don't define shared memory block's name in case of # the failure when we run multiprocessing tests in parallel. diff --git a/Misc/NEWS.d/next/Library/2020-07-20-13-27-48.bpo-41344.iKipNd.rst b/Misc/NEWS.d/next/Library/2020-07-20-13-27-48.bpo-41344.iKipNd.rst new file mode 100644 index 00000000000000..475bc9bddb0d54 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-07-20-13-27-48.bpo-41344.iKipNd.rst @@ -0,0 +1 @@ +Prevent creating :class:`shared_memory.SharedMemory` objects with :code:`size=0`.