linux-kernel - Re: [PATCH] rust: dma: add `Send` implementation for `CoherentAllocation`

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <67e19dcb.050a0220.bdc26.35e5@mx.google.com>
Date: Mon, 24 Mar 2025 11:00:40 -0700
From: Boqun Feng <boqun.feng@...il.com>
To: Miguel Ojeda <ojeda@...nel.org>
Cc: Abdiel Janulgue <abdiel.janulgue@...il.com>,
	Danilo Krummrich <dakr@...nel.org>,
	Alex Gaynor <alex.gaynor@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	Daniel Almeida <daniel.almeida@...labora.com>,
	Robin Murphy <robin.murphy@....com>,
	Andreas Hindborg <a.hindborg@...nel.org>,
	rust-for-linux@...r.kernel.org, Gary Guo <gary@...yguo.net>,
	Björn Roy Baron <bjorn3_gh@...tonmail.com>,
	Benno Lossin <benno.lossin@...ton.me>,
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>,
	"Rafael J. Wysocki" <rafael@...nel.org>, linux-next@...r.kernel.org,
	linux-kernel@...r.kernel.org, patches@...ts.linux.dev
Subject: Re: [PATCH] rust: dma: add `Send` implementation for
 `CoherentAllocation`

On Mon, Mar 24, 2025 at 06:40:48PM +0100, Miguel Ojeda wrote:
> From: Danilo Krummrich <dakr@...nel.org>
> 
> Stephen found a future build failure in linux-next [1]:
> 
>     error[E0277]: `*mut MyStruct` cannot be sent between threads safely
>       --> samples/rust/rust_dma.rs:47:22
>        |
>     47 | impl pci::Driver for DmaSampleDriver {
>        |                      ^^^^^^^^^^^^^^^ `*mut MyStruct` cannot be sent between threads safely
> 
> It is caused by the interaction between commit 935e1d90bf6f ("rust: pci:
> require Send for Driver trait implementers") from the driver-core tree,
> which fixes a missing concurrency requirement, and commit 9901addae63b
> ("samples: rust: add Rust dma test sample driver") which adds a sample
> that does not satisfy that requirement.
> 
> Add a `Send` implementation to `CoherentAllocation`, which allows the
> sample (and other future users) to satisfy it.
> 
> Reported-by: Stephen Rothwell <sfr@...b.auug.org.au>
> Closes: https://lore.kernel.org/linux-next/20250324215702.1515ba92@canb.auug.org.au/
> Signed-off-by: Danilo Krummrich <dakr@...nel.org>
> Signed-off-by: Miguel Ojeda <ojeda@...nel.org>
> ---
>  rust/kernel/dma.rs | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/rust/kernel/dma.rs b/rust/kernel/dma.rs
> index 9d00f9c49f47..18de693c4924 100644
> --- a/rust/kernel/dma.rs
> +++ b/rust/kernel/dma.rs
> @@ -301,6 +301,10 @@ fn drop(&mut self) {
>      }
>  }
>  
> +// SAFETY: It is safe to send a `CoherentAllocation` to another thread if `T`
> +// can be send to another thread.

s/can be send/can be sent

Reviewed-by: Boqun Feng <boqun.feng@...il.com>

Regards,
Boqun

> +unsafe impl<T: AsBytes + FromBytes + Send> Send for CoherentAllocation<T> {}
> +
>  /// Reads a field of an item from an allocated region of structs.
>  ///
>  /// # Examples
> -- 
> 2.49.0
>