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Code Issues Projects Releases Packages Wiki Activity Actions 8

GH-99729: Unlink frames before clearing them (GH-100030)

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Brandt Bucher 2022-12-06 06:01:38 -08:00 • committed by GitHub
parent 85d5a7e8ef
commit b72014c783
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GPG key ID: 4AEE18F83AFDEB23
6 changed files with 60 additions and 11 deletions
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5
Python/bytecodes.c
View file

@ -619,7 +619,10 @@ dummy_func(
DTRACE_FUNCTION_EXIT();
_Py_LeaveRecursiveCallPy(tstate);
assert(frame != &entry_frame);
frame = cframe.current_frame = pop_frame(tstate, frame);
// GH-99729: We need to unlink the frame *before* clearing it:
_PyInterpreterFrame *dying = frame;
frame = cframe.current_frame = dying->previous;
_PyEvalFrameClearAndPop(tstate, dying);
_PyFrame_StackPush(frame, retval);
goto resume_frame;
}

13
Python/ceval.c
View file

@ -1009,14 +1009,6 @@ trace_function_exit(PyThreadState *tstate, _PyInterpreterFrame *frame, PyObject
return 0;
}
static _PyInterpreterFrame *
pop_frame(PyThreadState *tstate, _PyInterpreterFrame *frame)
{
_PyInterpreterFrame *prev_frame = frame->previous;
_PyEvalFrameClearAndPop(tstate, frame);
return prev_frame;
}
int _Py_CheckRecursiveCallPy(
PyThreadState *tstate)
@ -1432,7 +1424,10 @@ exit_unwind:
assert(_PyErr_Occurred(tstate));
_Py_LeaveRecursiveCallPy(tstate);
assert(frame != &entry_frame);
frame = cframe.current_frame = pop_frame(tstate, frame);
// GH-99729: We need to unlink the frame *before* clearing it:
_PyInterpreterFrame *dying = frame;
frame = cframe.current_frame = dying->previous;
_PyEvalFrameClearAndPop(tstate, dying);
if (frame == &entry_frame) {
/* Restore previous cframe and exit */
tstate->cframe = cframe.previous;

3
Python/frame.c
View file

@ -127,6 +127,9 @@ _PyFrame_Clear(_PyInterpreterFrame *frame)
* to have cleared the enclosing generator, if any. */
assert(frame->owner != FRAME_OWNED_BY_GENERATOR ||
_PyFrame_GetGenerator(frame)->gi_frame_state == FRAME_CLEARED);
// GH-99729: Clearing this frame can expose the stack (via finalizers). It's
// crucial that this frame has been unlinked, and is no longer visible:
assert(_PyThreadState_GET()->cframe->current_frame != frame);
if (frame->frame_obj) {
PyFrameObject *f = frame->frame_obj;
frame->frame_obj = NULL;

5
Python/generated_cases.c.h generated
View file

@ -628,7 +628,10 @@
DTRACE_FUNCTION_EXIT();
_Py_LeaveRecursiveCallPy(tstate);
assert(frame != &entry_frame);
frame = cframe.current_frame = pop_frame(tstate, frame);
// GH-99729: We need to unlink the frame *before* clearing it:
_PyInterpreterFrame *dying = frame;
frame = cframe.current_frame = dying->previous;
_PyEvalFrameClearAndPop(tstate, dying);
_PyFrame_StackPush(frame, retval);
goto resume_frame;
}