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gh-136421: Fix crash when _datetime is been initialized in multiple sub-interpreters #136422

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gh-136421: Fix crash when _datetime is been initialized in multiple sub-interpreters #136422

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f1e7225
Fix crash when _datetime is been initialized in multiple sub-interpre…
aisk Jul 8, 2025
b6735f6
Fix RST markers
aisk Jul 8, 2025
67cf8fd
Simplify the codes
aisk Jul 8, 2025
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core_and_Builtins/2025-07-08-23-00-58.gh-issue-136421.uzieFA.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fix a crash when ``_datetime`` is being imported in multiple
sub-interpreters at the same time.
6 changes: 5 additions & 1 deletion Modules/_datetimemodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -7344,9 +7344,13 @@ init_static_types(PyInterpreterState *interp, int reloading)

/* Bases classes must be initialized before subclasses,
* so capi_types must have the types in the appropriate order. */
static PyMutex mutex = {0};
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If the assumption is that this can run concurrently, then we need to also protect the assignments to tp_base above.

for (size_t i = 0; i < Py_ARRAY_LENGTH(capi_types); i++) {
PyTypeObject *type = capi_types[i];
if (_PyStaticType_InitForExtension(interp, type) < 0) {
PyMutex_Lock(&mutex);
int ret = _PyStaticType_InitForExtension(interp, type);
PyMutex_Unlock(&mutex);
Comment on lines +7350 to +7352
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A lock needs to be applied to whole the loop or function rather than to a type to avoid a crash here (for me), because all managed static extension types are currently supposed to be indexed by using the same interpreter:

cpython/Objects/typeobject.c

Lines 322 to 329 in db47f4d

else {
PyMutex_Lock(&interp->types.mutex);
index = interp->types.for_extensions.next_index;
interp->types.for_extensions.next_index++;
PyMutex_Unlock(&interp->types.mutex);
assert(index < _Py_MAX_MANAGED_STATIC_EXT_TYPES);
}
managed_static_type_index_set(self, index);

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A lock needs to be applied to whole the loop or function

Hmm, still crashes with many workers...

if (ret < 0) {
return -1;
}
}
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