Re: [PATCH v2] rust: DmaFence: Remove static lifetime

From: Philipp Stanner

Date: Fri Oct 16 2026 - 08:12:28 EST


On Wed, 2026-09-30 at 14:27 +0200, Philipp Stanner wrote:
> A FenceCallbackRegistration can stem from another party than the one
> that has created a Fence. Should that party forget the registration
> object (for example through a refcount cycle) and then unload the
> module, a fence signaling would run into the unloaded module, causing
> UAF bugs.
>
> So far, this has been solved by demanding that the payload data of the
> registration object demanding static lifetime.
>
> It turns out, however, that this is harmful because the static lifetime
> bubbles up to all users, ultimately potentially causing a large amount
> of driver data to be static, which renders the lifetime obsolete.
>
> Solve this issue instead through an unsafe requirement which demands
> that the user does not forget the registration object. This is also the
> solution chosen by ScopedWork.
>
> Suggested-by: Danilo Krummrich <dakr@xxxxxxxxxx>
> Signed-off-by: Philipp Stanner <phasta@xxxxxxxxxx>
> Reviewed-by: Onur Özkan <work@xxxxxxxxxxxxx>

Gentle ping about the merge since we need this to upstream
drm::JobQueue


P.