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

From: "Danilo Krummrich" <[email-masked]>
Date: Fri, 07 Nov 2025 10:05:48 +0100

On Fri Nov 7, 2025 at 3:41 AM CET, Stephen Rothwell wrote:
> Caused by commit
>
>   a9fca8a7b2c5 ("rust: debugfs: support blobs from smart pointers")
>
> (maybe interacting with some other change).

This is a conflict with commit da123f0ee40f ("rust: lock: guard: Add T: Unpin
bound to DerefMut") from the tip tree.

The following diff [1] should fix the problem; I will also add a patch in the
driver-core tree for this, since this also works without the above commit.

diff --git a/rust/kernel/debugfs/traits.rs b/rust/kernel/debugfs/traits.rs
index 6bd21ff0ed90..7266c39188ba 100644
--- a/rust/kernel/debugfs/traits.rs
+++ b/rust/kernel/debugfs/traits.rs
@@ -257,7 +257,7 @@ fn read_from_slice(
 }

 // Delegate for `Mutex<T>`: Support a `T` with an outer `Mutex`.
-impl<T: BinaryReaderMut> BinaryReader for Mutex<T> {
+impl<T: BinaryReaderMut + Unpin> BinaryReader for Mutex<T> {
     fn read_from_slice(
         &self,
         reader: &mut UserSliceReader,