bpo-32604: Swap threads only if the interpreter is different. (gh-5778)

The CPython runtime assumes that there is a one-to-one relationship (for a given interpreter) between PyThreadState and OS threads. Sending and receiving on a channel in the same interpreter was causing crashes because of this (specifically due to a check in PyThreadState_Swap()). The solution is to not switch threads if the interpreter is the same.
This commit is contained in:
Eric Snow 2018-02-20 16:30:17 -07:00 committed by GitHub
parent 80d20b918b
commit f53d9f2778
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 77 additions and 14 deletions

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@ -331,9 +331,10 @@ _PyInterpreterState_IDDecref(PyInterpreterState *interp)
PyThread_release_lock(interp->id_mutex);
if (refcount == 0) {
PyThreadState *tstate, *save_tstate;
tstate = PyInterpreterState_ThreadHead(interp);
save_tstate = PyThreadState_Swap(tstate);
// XXX Using the "head" thread isn't strictly correct.
PyThreadState *tstate = PyInterpreterState_ThreadHead(interp);
// XXX Possible GILState issues?
PyThreadState *save_tstate = PyThreadState_Swap(tstate);
Py_EndInterpreter(tstate);
PyThreadState_Swap(save_tstate);
}
@ -1213,8 +1214,14 @@ _PyCrossInterpreterData_Release(_PyCrossInterpreterData *data)
}
return;
}
PyThreadState *tstate = PyInterpreterState_ThreadHead(interp);
PyThreadState *save_tstate = PyThreadState_Swap(tstate);
PyThreadState *save_tstate = NULL;
if (interp != PyThreadState_Get()->interp) {
// XXX Using the "head" thread isn't strictly correct.
PyThreadState *tstate = PyInterpreterState_ThreadHead(interp);
// XXX Possible GILState issues?
save_tstate = PyThreadState_Swap(tstate);
}
// "Release" the data and/or the object.
if (data->free != NULL) {
@ -1223,8 +1230,9 @@ _PyCrossInterpreterData_Release(_PyCrossInterpreterData *data)
Py_XDECREF(data->obj);
// Switch back.
if (save_tstate != NULL)
if (save_tstate != NULL) {
PyThreadState_Swap(save_tstate);
}
}
PyObject *