diff --git a/Cargo.toml b/Cargo.toml
index 37a76cdd34f..a1c9ad79621 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -29,6 +29,7 @@ exit = "warn"
 tests_outside_test_module = "warn"
 assertions_on_result_states = "warn"
 error_impl_error = "warn"
+or_fun_call = "warn"
 
 [profile.dev]
 panic = "abort"
diff --git a/src/clippy-tracing/src/main.rs b/src/clippy-tracing/src/main.rs
index c89fb6a5d37..721fca12b25 100644
--- a/src/clippy-tracing/src/main.rs
+++ b/src/clippy-tracing/src/main.rs
@@ -260,7 +260,7 @@ impl Error for ExecError {}
 fn exec() -> Result<Option<(PathBuf, usize, usize)>, ExecError> {
     let args = CommandLineArgs::parse();
 
-    let path = args.path.unwrap_or(PathBuf::from("."));
+    let path = args.path.unwrap_or_else(|| PathBuf::from("."));
     for entry_res in WalkDir::new(path).follow_links(true) {
         let entry = entry_res.map_err(ExecError::Entry)?;
         let entry_path = entry.into_path();
diff --git a/src/cpu-template-helper/src/template/verify/mod.rs b/src/cpu-template-helper/src/template/verify/mod.rs
index 1a83f6ba1b2..1f42e2f06cc 100644
--- a/src/cpu-template-helper/src/template/verify/mod.rs
+++ b/src/cpu-template-helper/src/template/verify/mod.rs
@@ -43,7 +43,7 @@ where
     for (key, template_value_filter) in template {
         let config_value_filter = config
             .get(&key)
-            .ok_or(VerifyError::KeyNotFound(key.to_string()))?;
+            .ok_or_else(|| VerifyError::KeyNotFound(key.to_string()))?;
 
         let template_value = template_value_filter.value & template_value_filter.filter;
         let config_value = config_value_filter.value & template_value_filter.filter;
diff --git a/src/vmm/src/vstate/vm.rs b/src/vmm/src/vstate/vm.rs
index aeb61f88c56..8c4049f9e0c 100644
--- a/src/vmm/src/vstate/vm.rs
+++ b/src/vmm/src/vstate/vm.rs
@@ -170,9 +170,9 @@ impl InterruptSourceGroup for MsiVectorGroup {
 
     fn trigger(&self, index: InterruptIndex) -> vm_device::interrupt::Result<()> {
         self.notifier(index)
-            .ok_or(std::io::Error::other(format!(
-                "trigger: invalid interrupt index {index}"
-            )))?
+            .ok_or_else(|| {
+                std::io::Error::other(format!("trigger: invalid interrupt index {index}"))
+            })?
             .write(1)
     }