---
# System prepended metadata

title: Meeting 2023-11-01
tags: [meeting notes]

---

# Meeting 2023-11-01
<!-- Leave your topic starting with ### in the relevant sections below -->

## Critical
<!-- bugs, soundness issues, urgent patches/reviews etc. -->

* [x] No open meeting this rc-1 (since it conflicts with LPC)
* [x] More reschedule due to daylight saving end?

## Status Reports
<!-- You want to report on something you are working on/request reviews.
Or you want to know the status of something someone else is doing -->

### Binder RFC was sent

https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@google.com/

## Discussion Questions
<!-- Anything that requires lengthy discussion/more general questions also fit here -->

### `Opaque` is not enough

I just noticed this issue after the discussion about the data races on Tomo's patches.
`&mut T` asserts uniqueness even for `&mut UnsafeCell<T>`. There is [this discussion](https://rust-lang.zulipchat.com/#narrow/stream/136281-t-opsem/topic/UnsafeCellMut/near/308124014) on zulip, but I remember vaguely to have discussed it elsewhere as well.

The problem is that `UnsafeCell` has a **safe** function [`get_mut(&mut self) -> &mut T`](https://doc.rust-lang.org/core/cell/struct.UnsafeCell.html#method.get_mut) that would allow one to violate the intended guarantees of `&mut Opaque<T>`.

Question: What do we do about this?

Alice: `Opaque` is `!Unpin`, which means that `&mut T` does not assert uniqueness.

Benno: *facepalm* I totally forgot about this. Do we have this documented somewhere?

I think if not, then I will send another docs improvements patch :)

Here is the patch that made it `!Unpin`: https://lore.kernel.org/rust-for-linux/20230630150216.109789-1-benno.lossin@proton.me/ we did not talk about that at all.
So theoretically we had this issue before we changed this. Is this patch also in the stable tree?

See also: https://github.com/rust-lang/rfcs/pull/3467

### Modules as a config option

## Miscellaneous
<!-- stuff that does not fit into other categories -->
