diff --git a/src/riot-rs-bench/src/cortexm.rs b/src/riot-rs-bench/src/cortexm.rs
index 797e03daa..6f8894ac0 100644
--- a/src/riot-rs-bench/src/cortexm.rs
+++ b/src/riot-rs-bench/src/cortexm.rs
@@ -6,7 +6,7 @@ use cortex_m::{
 use crate::Error;
 
 #[allow(missing_docs)]
-pub fn benchmark<F: Fn() -> ()>(iterations: usize, f: F) -> Result<usize, Error> {
+pub fn benchmark<F: FnMut() -> ()>(iterations: usize, mut f: F) -> Result<usize, Error> {
     let mut p = unsafe { Peripherals::steal() };
     //
     p.SCB.clear_sleepdeep();
diff --git a/src/riot-rs-bench/src/esp.rs b/src/riot-rs-bench/src/esp.rs
index 45cf14f6f..8d4627064 100644
--- a/src/riot-rs-bench/src/esp.rs
+++ b/src/riot-rs-bench/src/esp.rs
@@ -6,7 +6,7 @@ use esp_hal::{
 use crate::Error;
 
 #[allow(missing_docs)]
-pub fn benchmark<F: Fn() -> ()>(iterations: usize, f: F) -> Result<usize, Error> {
+pub fn benchmark<F: FnMut() -> ()>(iterations: usize, mut f: F) -> Result<usize, Error> {
     let mut systimer_periph = unsafe { peripherals::SYSTIMER::steal() };
     let timer = SystemTimer::new(&mut systimer_periph);
 
diff --git a/src/riot-rs-bench/src/lib.rs b/src/riot-rs-bench/src/lib.rs
index 8c993bb73..4df0d41d7 100644
--- a/src/riot-rs-bench/src/lib.rs
+++ b/src/riot-rs-bench/src/lib.rs
@@ -29,7 +29,7 @@ cfg_if::cfg_if! {
             /// Returns [`Error::SystemTimerWrapped`] if the system timer counter has wrapped when
             /// benchmarking.
             #[allow(unused_variables)]
-            pub fn benchmark<F: Fn()>(iterations: usize, f: F) -> Result<usize, Error> {
+            pub fn benchmark<F: FnMut()>(iterations: usize, f: F) -> Result<usize, Error> {
                 unimplemented!();
             }
         }