Re: [PATCH v3 1/2] rust: workqueue: restrict delayed work to global wqs

["Danilo Krummrich" <dakr@kernel.org>]

On Fri Feb 27, 2026 at 3:53 PM CET, Alice Ryhl wrote:
> When a workqueue is shut down, delayed work that is pending but not
> scheduled does not get properly cleaned up, so it's not safe to use
> `enqueue_delayed` on a workqueue that might be destroyed. To fix this,
> restricted `enqueue_delayed` to static queues.

:(

Reviewed-by: Danilo Krummrich <dakr@kernel.org>

> Cc: stable@vger.kernel.org
> Fixes: 7c098cd5eaae ("workqueue: rust: add delayed work items")
> Reviewed-by: John Hubbard <jhubbard@nvidia.com>
> Signed-off-by: Alice Ryhl <aliceryhl@google.com>
> ---
>  rust/kernel/workqueue.rs | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
> index 706e833e9702..1acd113c04ee 100644
> --- a/rust/kernel/workqueue.rs
> +++ b/rust/kernel/workqueue.rs
> @@ -296,8 +296,15 @@ pub fn enqueue<W, const ID: u64>(&self, w: W) -> W::EnqueueOutput
>      ///
>      /// This may fail if the work item is already enqueued in a workqueue.
>      ///
> +    /// This is only valid for global workqueues (with static lifetimes) because those are the only
> +    /// ones that outlive all possible delayed work items.

We should probably add a FIXME comment pointing out that this should be fixed in
the C code.

Maybe also link your approach?

> +    ///
>      /// The work item will be submitted using `WORK_CPU_UNBOUND`.
> -    pub fn enqueue_delayed<W, const ID: u64>(&self, w: W, delay: Jiffies) -> W::EnqueueOutput
> +    pub fn enqueue_delayed<W, const ID: u64>(
> +        &'static self,
> +        w: W,
> +        delay: Jiffies,
> +    ) -> W::EnqueueOutput
>      where
>          W: RawDelayedWorkItem<ID> + Send + 'static,
>      {
>
> -- 
> 2.53.0.473.g4a7958ca14-goog