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bpo-41796: Call _PyAST_Fini() earlier to fix a leak (GH-23131)

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Call _PyAST_Fini() on all interpreters, not only on the main
interpreter. Also, call it ealier to fix a reference leak.

Python types contain a reference to themselves in in their
PyTypeObject.tp_mro member. _PyAST_Fini() must called before the last
GC collection to destroy AST types.

_PyInterpreterState_Clear() now calls _PyAST_Fini(). It now also
calls _PyWarnings_Fini() on subinterpeters, not only on the main
interpreter.

Add an assertion in AST init_types() to ensure that the _ast module
is no longer used after _PyAST_Fini() has been called.
This commit is contained in:
Victor Stinner 2020-11-03 18:07:15 +01:00 • committed by GitHub
parent 212d32f45c
commit fd957c124c
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GPG key ID: 4AEE18F83AFDEB23
5 changed files with 78 additions and 43 deletions
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67
Parser/asdl_c.py
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@ -1015,18 +1015,35 @@ static int add_ast_fields(struct ast_state *state)
""", 0, reflow=False)
self.emit("static int init_types(struct ast_state *state)",0)
self.emit("{", 0)
self.emit("if (state->initialized) return 1;", 1)
self.emit("if (init_identifiers(state) < 0) return 0;", 1)
self.emit("state->AST_type = PyType_FromSpec(&AST_type_spec);", 1)
self.emit("if (!state->AST_type) return 0;", 1)
self.emit("if (add_ast_fields(state) < 0) return 0;", 1)
self.file.write(textwrap.dedent('''
static int
init_types(struct ast_state *state)
{
// init_types() must not be called after _PyAST_Fini()
// has been called
assert(state->initialized >= 0);
if (state->initialized) {
return 1;
}
if (init_identifiers(state) < 0) {
return 0;
}
state->AST_type = PyType_FromSpec(&AST_type_spec);
if (!state->AST_type) {
return 0;
}
if (add_ast_fields(state) < 0) {
return 0;
}
'''))
for dfn in mod.dfns:
self.visit(dfn)
self.emit("state->initialized = 1;", 1)
self.emit("return 1;", 1);
self.emit("}", 0)
self.file.write(textwrap.dedent('''
state->initialized = 1;
return 1;
}
'''))
def visitProduct(self, prod, name):
if prod.fields:
@ -1353,23 +1370,27 @@ def generate_ast_state(module_state, f):
def generate_ast_fini(module_state, f):
f.write("""
void _PyAST_Fini(PyThreadState *tstate)
{
#ifdef Py_BUILD_CORE
struct ast_state *state = &tstate->interp->ast;
#else
struct ast_state *state = &global_ast_state;
#endif
f.write(textwrap.dedent("""
void _PyAST_Fini(PyInterpreterState *interp)
{
#ifdef Py_BUILD_CORE
struct ast_state *state = &interp->ast;
#else
struct ast_state *state = &global_ast_state;
#endif
""")
"""))
for s in module_state:
f.write(" Py_CLEAR(state->" + s + ');\n')
f.write("""
state->initialized = 0;
}
f.write(textwrap.dedent("""
#if defined(Py_BUILD_CORE) && !defined(NDEBUG)
state->initialized = -1;
#else
state->initialized = 0;
#endif
}
""")
"""))
def generate_module_def(mod, f, internal_h):