bpo-43551: fix PyImport_Import use static silly_list, under building Python with --with-experimental-isolated-subinterpreters share silly_list in multi sub interpreters cause crash. #24929
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JunyiXie
requested review from
brettcannon,
encukou,
ericsnowcurrently,
ncoghlan and
warsaw
as code owners
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Hello, this change seems might not need to update news. |
vstinner
reviewed
Mar 19, 2021
Python/import.c
Outdated
| @@ -1745,7 +1745,7 @@ PyObject * | |||
| PyImport_Import(PyObject *module_name) | |||
| { | |||
| PyThreadState *tstate = _PyThreadState_GET(); | |||
| static PyObject *silly_list = NULL; | |||
| PyObject *silly_list = NULL; | |||
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"silly list" is not a great name, I propose to rename it to "from_list".
Also you must put a DECREF somewhere, otherwise the code will leak.
vstinner
reviewed
Mar 19, 2021
| @@ -0,0 +1 @@ | |||
| fix PyImport_Import use static silly_list, under building Python with --with-experimental-isolated-subinterpreters share silly_list in multi sub interpreters cause crash. | |||
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--with-experimental-isolated-subinterpreters option is supposed to remain secret!
Either remove your NEWS entry, or just say "subinterpreters". For example, "Fix the import function for subinterpreters." I'm not sure that it's worth it to document every single subinterpreter fix.
vstinner
reviewed
Mar 20, 2021
Python/import.c
Outdated
Comment on lines
1749
to
1750
| static PyObject *builtins_str = NULL; | ||
| static PyObject *import_str = NULL; |
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static variables are bad, they don't work in subinterpreters. You can use the _Py_IDENTIFIER() API with _PyUnicode_FromId() (return a borrowed reference), it is compatible with subinterpreters.
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@vstinner thanks for your review. I have fix these problems. |
vstinner
reviewed
Mar 22, 2021
Python/import.c
Outdated
| if (silly_list == NULL) | ||
| return NULL; | ||
| } | ||
| import_str = _PyUnicode_FromId(&PyId___import__); |
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You can define the variable here (same for the 2 other variables) and add a comment to mention that it's a borrowed ref
Suggested change
| import_str = _PyUnicode_FromId(&PyId___import__); | |
| PyObject *import_str = _PyUnicode_FromId(&PyId___import__); // borrowed ref |
vstinner
reviewed
Mar 22, 2021
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There is a refleak (unrelated to your PR) at:
/* No globals -- use standard builtins, and fake globals */
builtins = PyImport_ImportModuleLevel("builtins",
NULL, NULL, NULL, 0);
if (builtins == NULL)
return NULL; // <=== HERE
Please replace return NULL with goto err and add braces (PEP 7).
You may also replace return NULL with goto err at:
PyObject *from_list = PyList_New(0);
if (from_list == NULL) {
return NULL;
}
You might also remove trailing spaces at line 1761 :-D (my text editor highlights them ;-))
under building Python with --with-experimental-isolated-subinterpreters share silly_list in multi subinterpreters cause crash.
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https://bugs.python.org/issue43551
fix PyImport_Import use static silly_list under building Python with --with-experimental-isolated-subinterpreters share silly_list in multi subinterpreters cause crash.
Under the sub interpreters parallel, PyObject_CallFunction clean stack,
Py_DECREF(stack[i]), Py_DECREF silly_list is not thread safe. cause crash
https://bugs.python.org/issue43551