linux-next: build failure after merge of the driver-core tree

Stephen Rothwell
2025-11-07T02:41:52Z

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Hi all,

After merging the driver-core tree, today's linux-next build (x86_64
allmodconfig) failed like this:

error: variable does not need to be mutable
--> rust/kernel/debugfs/traits.rs:266:13
|
266 | let mut this = self.lock();
| ----^^^^
| |
| help: remove this `mut`
|
= note: `-D unused-mut` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(unused_mut)]`

error[E0596]: cannot borrow data in dereference of `lock::Guard<'_, T, MutexBackend>` as mutable
--> rust/kernel/debugfs/traits.rs:268:9
|
268 | this.read_from_slice_mut(reader, offset)
| ^^^^ cannot borrow as mutable
|
= help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `lock::Guard<'_, T, MutexBackend>`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0596`.

Caused by commit

a9fca8a7b2c5 ("rust: debugfs: support blobs from smart pointers")

(maybe interacting with some other change).

I have used the driver-core tree from next-20251106 for today.

--
Cheers,
Stephen Rothwell

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