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asserting that the tstate pointer is non-NULL using assert #122928
Description
Bug report
Bug description:
https://github.com/python/cpython/blob/main/Python/pystate.c#L3016
To prevent dangling pointer issues, adding a check for NULL ensures that invalid pointers are not dereferenced
Activity
ZeroIntensity commentedon Aug 12, 2024
As mentioned in the PR, a
NULLcheck doesn't fix dangling pointers.With that being said, calling
_PyThreadState_MustExitwith an invalid thread state sounds like a bug, is there a specific case of this happening?neonene commentedon Aug 13, 2024
My understanding is that a problematic dangling pointer could be caused by the legacy non-isolated subinterpreter created with
Py_NewInterpreter(), allowing daemon threads. Now that Python uses and recommends the new isolated subinterpreter, I do not think the concern is worth much consideration.See also #109794 (comment), #104341 (comment).
picnixz commentedon Aug 14, 2024
I'm wondering whether the issue should still mention dangling pointer since a dangling pointer is a valid pointer (hence non-null) pointing to invalid memory. It's more about asserting that the pointer is non-NULL using
assert(namely, enforcing pre-conditions).neonene commentedon Aug 15, 2024
Please change the title, or make the PR belong to gh-109793. The current title is not good for closing here as "completed".
[-]tstate might be a dangling pointer[/-][+]asserting that the tstate pointer is non-NULL using assert[/+]vstinner commentedon Sep 18, 2024
The change is not needed: #122929 (review)