[PATCH 6.18 737/752] rust: irq: add `'static` bounds to irq callbacks

Sasha Levin
2026-02-28T17:59:13Z

From: Benno Lossin <lossin@kernel.org>

[ Upstream commit 621609f1e5ca43a75edd497dd1c28bd84aa66433 ]

These callback functions take a generic `T` that is used in the body as
the generic argument in `Registration` and `ThreadedRegistration`. Those
types require `T: 'static`, but due to a compiler bug this requirement
isn't propagated to the function. Thus add the bound. This was caught in
the upstream Rust CI [1].

[ The three errors looked similar and will start appearing with Rust
1.95.0 (expected 2026-04-16). The first one was:

error[E0310]: the parameter type `T` may not live long enough
Error: --> rust/kernel/irq/request.rs:266:43
|
266 | let registration = unsafe { &*(ptr as *const Registration<T>) };
| ^^^^^^^^^^^^^^^^^^^^^^
| |
| the parameter type `T` must be valid for the static lifetime...
| ...so that the type `T` will meet its required lifetime bounds
|
help: consider adding an explicit lifetime bound
|
264 | unsafe extern "C" fn handle_irq_callback<T: Handler + 'static>(_irq: i32, ptr: *mut c_void) -> c_uint {
| +++++++++

- Miguel ]

Link: https://github.com/rust-lang/rust/pull/149389 [1]
Signed-off-by: Benno Lossin <lossin@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 29e16fcd67ee ("rust: irq: add &Device<Bound> argument to irq callbacks")
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/rust-for-linux/20260217222425.8755-1-cole@unwrap.rs/
Link: https://patch.msgid.link/20260214092740.3201946-1-lossin@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
rust/kernel/irq/request.rs | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/irq/request.rs b/rust/kernel/irq/request.rs
index b150563fdef80..2ceeaeb0543a4 100644
--- a/rust/kernel/irq/request.rs
+++ b/rust/kernel/irq/request.rs
@@ -261,7 +261,10 @@ impl<T: Handler + 'static> Registration<T> {
/// # Safety
///
/// This function should be only used as the callback in `request_irq`.
-unsafe extern "C" fn handle_irq_callback<T: Handler>(_irq: i32, ptr: *mut c_void) -> c_uint {
+unsafe extern "C" fn handle_irq_callback<T: Handler + 'static>(
+ _irq: i32,
+ ptr: *mut c_void,
+) -> c_uint {
// SAFETY: `ptr` is a pointer to `Registration<T>` set in `Registration::new`
let registration = unsafe { &*(ptr as *const Registration<T>) };
// SAFETY: The irq callback is removed before the device is unbound, so the fact that the irq
@@ -480,7 +483,7 @@ impl<T: ThreadedHandler + 'static> ThreadedRegistration<T> {
/// # Safety
///
/// This function should be only used as the callback in `request_threaded_irq`.
-unsafe extern "C" fn handle_threaded_irq_callback<T: ThreadedHandler>(
+unsafe extern "C" fn handle_threaded_irq_callback<T: ThreadedHandler + 'static>(
_irq: i32,
ptr: *mut c_void,
) -> c_uint {
@@ -496,7 +499,10 @@ unsafe extern "C" fn handle_threaded_irq_callback<T: ThreadedHandler>(
/// # Safety
///
/// This function should be only used as the callback in `request_threaded_irq`.
-unsafe extern "C" fn thread_fn_callback<T: ThreadedHandler>(_irq: i32, ptr: *mut c_void) -> c_uint {
+unsafe extern "C" fn thread_fn_callback<T: ThreadedHandler + 'static>(
+ _irq: i32,
+ ptr: *mut c_void,
+) -> c_uint {
// SAFETY: `ptr` is a pointer to `ThreadedRegistration<T>` set in `ThreadedRegistration::new`
let registration = unsafe { &*(ptr as *const ThreadedRegistration<T>) };
// SAFETY: The irq callback is removed before the device is unbound, so the fact that the irq
--
2.51.0