executor: Add fallible from_waker getter

4 files changed, 20 insertions, 4 deletions

diff --git a/embassy-executor/CHANGELOG.md b/embassy-executor/CHANGELOG.md
index 8f1db7de7..cc4027fca 100644
--- a/embassy-executor/CHANGELOG.md
+++ b/embassy-executor/CHANGELOG.md
@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Migrate `cortex-ar` to `aarch32-cpu`. The feature name `arch-cortex-ar` remains the same and
   legacy ARM architectures are not supported.
 - Added `run_until` to `arch-std` variant of `Executor`.
+- Added `__try_embassy_time_queue_item_from_waker`
 
 ## 0.9.1 - 2025-08-31
 
diff --git a/embassy-executor/src/raw/mod.rs b/embassy-executor/src/raw/mod.rs
index ab845ed3b..2b7560de6 100644
--- a/embassy-executor/src/raw/mod.rs
+++ b/embassy-executor/src/raw/mod.rs
@@ -49,6 +49,7 @@ use self::run_queue::{RunQueue, RunQueueItem};
 use self::state::State;
 use self::util::{SyncUnsafeCell, UninitCell};
 pub use self::waker::task_from_waker;
+use self::waker::try_task_from_waker;
 use super::SpawnToken;
 use crate::{Metadata, SpawnError};
 
@@ -57,6 +58,11 @@ extern "Rust" fn __embassy_time_queue_item_from_waker(waker: &Waker) -> &'static
     unsafe { task_from_waker(waker).timer_queue_item() }
 }
 
+#[unsafe(no_mangle)]
+extern "Rust" fn __try_embassy_time_queue_item_from_waker(waker: &Waker) -> Option<&'static mut TimerQueueItem> {
+    unsafe { try_task_from_waker(waker).map(|task| task.timer_queue_item()) }
+}
+
 /// Raw task header for use in task pointers.
 ///
 /// A task can be in one of the following states:
diff --git a/embassy-executor/src/raw/waker.rs b/embassy-executor/src/raw/waker.rs
index 2706f0fdf..8416f9f93 100644
--- a/embassy-executor/src/raw/waker.rs
+++ b/embassy-executor/src/raw/waker.rs
@@ -32,13 +32,18 @@ pub(crate) unsafe fn from_task(p: TaskRef) -> Waker {
 ///
 /// Panics if the waker is not created by the Embassy executor.
 pub fn task_from_waker(waker: &Waker) -> TaskRef {
+    unwrap!(
+        try_task_from_waker(waker),
+        "Found waker not created by the Embassy executor. Unless the generic timer queue is enabled, `embassy_time::Timer` only works with the Embassy executor."
+    )
+}
+
+pub(crate) fn try_task_from_waker(waker: &Waker) -> Option<TaskRef> {
     // make sure to compare vtable addresses. Doing `==` on the references
     // will compare the contents, which is slower.
     if waker.vtable() as *const _ != &VTABLE as *const _ {
-        panic!(
-            "Found waker not created by the Embassy executor. `embassy_time::Timer` only works with the Embassy executor."
-        )
+        return None;
     }
     // safety: our wakers are always created with `TaskRef::as_ptr`
-    unsafe { TaskRef::from_ptr(waker.data() as *const TaskHeader) }
+    Some(unsafe { TaskRef::from_ptr(waker.data() as *const TaskHeader) })
 }
diff --git a/embassy-executor/src/raw/waker_turbo.rs b/embassy-executor/src/raw/waker_turbo.rs
index 919bcc61a..ee33e7633 100644
--- a/embassy-executor/src/raw/waker_turbo.rs
+++ b/embassy-executor/src/raw/waker_turbo.rs
@@ -25,6 +25,10 @@ pub fn task_from_waker(waker: &Waker) -> TaskRef {
     unsafe { TaskRef::from_ptr(ptr as *const TaskHeader) }
 }
 
+pub(crate) fn try_task_from_waker(waker: &Waker) -> Option<TaskRef> {
+    Some(task_from_waker(waker))
+}
+
 #[inline(never)]
 #[unsafe(no_mangle)]
 fn _turbo_wake(ptr: NonNull<()>) {