diff --git a/kernel/src/syscall/mod.rs b/kernel/src/syscall/mod.rs
index 3504429..05406ab 100644
--- a/kernel/src/syscall/mod.rs
+++ b/kernel/src/syscall/mod.rs
@@ -82,7 +82,7 @@ pub fn syscall(id: usize, args: [usize; 6], tf: &mut TrapFrame) -> isize {
         059 => sys_exec(args[0] as *const u8, args[1] as *const *const u8, args[2] as *const *const u8, tf),
         060 => sys_exit(args[0] as usize),
         061 => sys_wait4(args[0] as isize, args[1] as *mut i32), // TODO: wait4
-        062 => sys_kill(args[0]),
+        062 => sys_kill(args[0], args[1]),
         063 => sys_uname(args[0] as *mut u8),
 //        072 => sys_fcntl(),
         074 => sys_fsync(args[0]),
diff --git a/kernel/src/syscall/proc.rs b/kernel/src/syscall/proc.rs
index 851f8fd..c5a1f9c 100644
--- a/kernel/src/syscall/proc.rs
+++ b/kernel/src/syscall/proc.rs
@@ -146,13 +146,35 @@ pub fn sys_yield() -> SysResult {
 }
 
 /// Kill the process
-pub fn sys_kill(pid: usize) -> SysResult {
-    info!("{} killed: {}", thread::current().id(), pid);
-    processor().manager().exit(pid, 0x100);
-    if pid == thread::current().id() {
-        processor().yield_now();
+pub fn sys_kill(pid: usize, sig: usize) -> SysResult {
+    info!("kill: {} killed: {} with sig {}", thread::current().id(), pid, sig);
+    let current_pid = process().pid.get().clone();
+    if current_pid == pid {
+        // killing myself
+        sys_exit_group(sig);
+        Ok(0)
+    } else {
+        if let Some(proc_arc) = PROCESSES.read().get(&pid).and_then(|weak| weak.upgrade()) {
+            let proc = proc_arc.lock();
+            // quit all threads
+            for tid in proc.threads.iter() {
+                processor().manager().exit(*tid, sig);
+            }
+            // notify parent and fill exit code
+            // avoid deadlock
+            let proc_parent = proc.parent.clone();
+            let pid = proc.pid.get();
+            drop(proc);
+            if let Some(parent) = proc_parent {
+                let mut parent = parent.lock();
+                parent.child_exit_code.insert(pid, sig);
+                parent.child_exit.notify_one();
+            }
+            Ok(0)
+        } else {
+            Err(SysError::EINVAL)
+        }
     }
-    Ok(0)
 }
 
 /// Get the current process id
diff --git a/tests/fork.exp b/tests/fork.exp
index a105ea7..49d9c1e 100644
--- a/tests/fork.exp
+++ b/tests/fork.exp
@@ -5,8 +5,8 @@ sleep 2
 expect ">>"
 sleep 2
 send -- "biscuit/fork\r"
-sleep 2
+sleep 5
 expect "hello from 100"
 expect "parent done!"
 send -- "^Ax"
-wait -nowait
+wait
diff --git a/tests/killtest.exp b/tests/killtest.exp
new file mode 100644
index 0000000..22c84b6
--- /dev/null
+++ b/tests/killtest.exp
@@ -0,0 +1,11 @@
+set timeout -1
+cd ../kernel
+spawn make run arch=x86_64
+sleep 2
+expect ">>"
+sleep 2
+send -- "biscuit/killtest\r"
+sleep 2
+expect "success"
+send -- "^Ax"
+wait
diff --git a/user b/user
index 091b95f..095cfa8 160000
--- a/user
+++ b/user
@@ -1 +1 @@
-Subproject commit 091b95fae21bf42c8ee403056bda830f65255286
+Subproject commit 095cfa8e66792544e491945eec18daad3e6d58b3