rust: drm: ioctl: fix unbounded lifetimes in ioctl handler arguments

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References to dev, data, and file in the declare_drm_ioctls! macro are
created via unsafe pointer dereferences, producing unbounded lifetimes.
If an ioctl handler explicitly annotates its parameters with 'static,
the compiler accepts this, allowing the handler to stash references that
outlive the ioctl call.

Fix this by adding a higher-ranked function pointer coercion that
enforces the handler accepts universally quantified lifetimes:

  let _: for<'a> fn(&'a _, &'a mut _, &'a _) -> _ = $func;

Since the handler must be coercible to a function pointer accepting any
lifetime 'a, it can no longer demand 'static on any parameter.

Cc: stable@vger.kernel.org
Fixes: 9a69570682 ("rust: drm: ioctl: Add DRM ioctl abstraction")
Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/all/20260620011346.A47D01F000E9@smtp.kernel.org/
Suggested-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Tested-by: Deborah Brouwer <deborah.brouwer@collabora.com>
Link: https://patch.msgid.link/20260628145406.2107056-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>

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Danilo Krummrich 2026-06-28 16:53:21 +02:00

parent d85845b64c

commit 68b151bc61

1 changed files with 6 additions and 0 deletions

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rust/kernel/drm/ioctl.rs

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