Fix UB: Non-static callbacks are unsound

src/gpio.rs

@@ -1147,17 +1147,18 @@ impl<'d, T: Pin, MODE> PinDriver<'d, T, MODE> {
     /// Care should be taken not to call STD, libc or FreeRTOS APIs (except for a few allowed ones)
     /// in the callback passed to this function, as it is executed in an ISR context.
     #[cfg(all(not(feature = "riscv-ulp-hal"), feature = "alloc"))]
-    pub unsafe fn subscribe(&mut self, callback: impl FnMut() + Send + 'd) -> Result<(), EspError>
+    pub unsafe fn subscribe<F>(&mut self, callback: F) -> Result<(), EspError>
     where
+        F: FnMut() + Send + 'static,
         MODE: InputMode,
     {
         extern crate alloc;
 
         self.disable_interrupt()?;
 
-        let callback: alloc::boxed::Box<dyn FnMut() + Send + 'd> = alloc::boxed::Box::new(callback);
-        chip::PIN_ISR_HANDLER[self.pin.pin() as usize] =
-            Some(unsafe { core::mem::transmute(callback) });
+        let callback: alloc::boxed::Box<dyn FnMut() + Send + 'static> =
+            alloc::boxed::Box::new(callback);
+        chip::PIN_ISR_HANDLER[self.pin.pin() as usize] = Some(callback);
 
         Ok(())
     }

src/pcnt.rs

@@ -459,9 +459,9 @@ impl<'d> PcntDriver<'d> {
     /// - ()
     /// - EspError
     #[cfg(feature = "alloc")]
-    pub unsafe fn subscribe<C>(&self, callback: C) -> Result<(), EspError>
+    pub unsafe fn subscribe<F>(&self, callback: F) -> Result<(), EspError>
     where
-        C: FnMut(u32) + Send + 'static,
+        F: FnMut(u32) + Send + 'static,
     {
         enable_isr_service()?;
 

src/timer.rs

@@ -287,15 +287,18 @@ impl<'d> TimerDriver<'d> {
     /// Care should be taken not to call STD, libc or FreeRTOS APIs (except for a few allowed ones)
     /// in the callback passed to this function, as it is executed in an ISR context.
     #[cfg(feature = "alloc")]
-    pub unsafe fn subscribe(&mut self, callback: impl FnMut() + Send + 'd) -> Result<(), EspError> {
+    pub unsafe fn subscribe<F>(&mut self, callback: F) -> Result<(), EspError>
+    where
+        F: FnMut() + Send + 'static,
+    {
         self.check();
 
         self.disable_interrupt()?;
 
-        let callback: Box<dyn FnMut() + Send + 'd> = Box::new(callback);
+        let callback: Box<dyn FnMut() + Send + 'static> = Box::new(callback);
 
         ISR_HANDLERS[(self.group() * timer_idx_t_TIMER_MAX + self.index()) as usize] =
-            Some(unsafe { core::mem::transmute(callback) });
+            Some(callback);
 
         Ok(())
     }