diff --git a/src/kernel/synch.rs b/src/kernel/synch.rs
index 0baa892..807793f 100644
--- a/src/kernel/synch.rs
+++ b/src/kernel/synch.rs
@@ -34,6 +34,7 @@ impl Semaphore {
 /// counter of 1
 /// It's used for critical parts
 #[derive(PartialEq)]
+#[derive(Clone)]
 pub struct Lock {
 
     /// Thread owning the lock
diff --git a/src/kernel/thread_manager.rs b/src/kernel/thread_manager.rs
index 26911b8..0f98417 100644
--- a/src/kernel/thread_manager.rs
+++ b/src/kernel/thread_manager.rs
@@ -282,8 +282,47 @@ impl ThreadManager {
         }
     }
 
-    pub fn lock_release(&mut self, id: i32, machine: &mut Machine) -> Result<MachineOk, MachineError>{
-        todo!()
+    ///     Wake up a waiter if necessary, or release it if no thread is waiting.
+    pub fn lock_release(&mut self, id: i32, machine: &mut Machine) -> Result<MachineOk, MachineError> {
+        let current_thread = self.get_g_current_thread();
+        match current_thread {
+            Some(thread) => {
+                let current_thread = Rc::clone(&thread);
+
+                let mut lock_option = self.get_obj_addrs().search_lock(id).cloned();
+                match lock_option {
+                    Some(mut lock) => {
+                        let old_status = machine.interrupt.set_status(InterruptStatus::InterruptOff);
+
+                        match &lock.owner {
+                            Some(lock_owner) => {
+                                if Rc::ptr_eq(&current_thread, lock_owner) {
+                                    match lock.waiting_queue.pop() {
+                                        Some(thread) => {
+                                            lock.owner = Some(thread);
+                                            match &lock.owner {
+                                                Some(x) => self.ready_to_run(Rc::clone(x)),
+                                                None => ()
+                                            }
+                                        },
+                                        None => {
+                                            lock.free = true;
+                                            lock.owner = None;
+                                        }
+                                    }
+                                }
+                            },
+                            None => ()
+                        }
+                        machine.interrupt.set_status(old_status);
+                        Ok(MachineOk::Ok)
+                    },
+                    None => Err("Cannot find lock")?
+                }
+            },
+            None => unreachable!("Current thread should not be None")
+        }
+
     }
 
     /// Currently running thread
diff --git a/src/utility/list.rs b/src/utility/list.rs
index adc08fa..7a90d0a 100644
--- a/src/utility/list.rs
+++ b/src/utility/list.rs
@@ -10,6 +10,7 @@ use std::ptr;
 /// but everything has been tested with miri to assure there's no Undefined Behaviour (use-after-free, double free, etc.)
 /// or memory leak
 #[derive(PartialEq)]
+#[derive(Clone)]
 pub struct List<T: PartialEq> {
     head: Link<T>,
     tail: *mut Node<T>,