cpython: 1a955981b263 (original) (raw)

Mercurial > cpython

changeset 105574:1a955981b263 3.5

Issue #28779: multiprocessing.set_forkserver_preload() would crash the forkserver process if a preloaded module instantiated some multiprocessing objects such as locks. [#28779]

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--- a/Lib/multiprocessing/context.py +++ b/Lib/multiprocessing/context.py @@ -195,7 +195,7 @@ class BaseContext(object): def get_start_method(self, allow_none=False): return self._name

• def set_start_method(self, method=None):

• def set_start_method(self, method, force=False): raise ValueError('cannot set start method of concrete context')

def _check_available(self):

--- a/Lib/multiprocessing/spawn.py +++ b/Lib/multiprocessing/spawn.py @@ -218,7 +218,7 @@ def prepare(data): process.ORIGINAL_DIR = data['orig_dir'] if 'start_method' in data:

•    set_start_method(data['start_method'])[](#l2.7)

•    set_start_method(data['start_method'], force=True)[](#l2.8)

if 'init_main_from_name' in data: _fixup_main_from_name(data['init_main_from_name'])

--- a/Lib/test/_test_multiprocessing.py +++ b/Lib/test/_test_multiprocessing.py @@ -3728,6 +3728,19 @@ class TestStartMethod(unittest.TestCase) self.assertTrue(methods == ['fork', 'spawn'] or methods == ['fork', 'spawn', 'forkserver'])

• def test_preload_resources(self):

•    if multiprocessing.get_start_method() != 'forkserver':[](#l3.8)

•        self.skipTest("test only relevant for 'forkserver' method")[](#l3.9)

•    name = os.path.join(os.path.dirname(__file__), 'mp_preload.py')[](#l3.10)

•    rc, out, err = test.support.script_helper.assert_python_ok(name)[](#l3.11)

•    out = out.decode()[](#l3.12)

•    err = err.decode()[](#l3.13)

•    if out.rstrip() != 'ok' or err != '':[](#l3.14)

•        print(out)[](#l3.15)

•        print(err)[](#l3.16)

•        self.fail("failed spawning forkserver or grandchild")[](#l3.17)

+ + #

Check that killing process does not leak named semaphores

#

new file mode 100644 --- /dev/null +++ b/Lib/test/mp_preload.py @@ -0,0 +1,18 @@ +import multiprocessing + +multiprocessing.Lock() + + +def f():

• print("ok")

+ + +if name == "main":

• ctx = multiprocessing.get_context("forkserver")
• modname = "test.mp_preload"

• Make sure it's importable

• import(modname)
• ctx.set_forkserver_preload([modname])
• proc = ctx.Process(target=f)
• proc.start()
• proc.join()

--- a/Misc/NEWS +++ b/Misc/NEWS @@ -124,6 +124,10 @@ Core and Builtins Library ------- +- Issue #28779: multiprocessing.set_forkserver_preload() would crash the

• forkserver process if a preloaded module instantiated some
• multiprocessing objects such as locks. +

• Issue #28847: dbm.dumb now supports reading read-only files and no longer writes the index file when it is not changed.