diff --git a/kernel/aster-nix/src/process/process/mod.rs b/kernel/aster-nix/src/process/process/mod.rs
index 4f5a2bd09..6274f2a43 100644
--- a/kernel/aster-nix/src/process/process/mod.rs
+++ b/kernel/aster-nix/src/process/process/mod.rs
@@ -49,7 +49,7 @@ pub type Pgid = u32;
 /// Session Id.
 pub type Sid = u32;
 
-pub type ExitCode = i32;
+pub type ExitCode = u32;
 
 pub(super) fn init() {
     timer_manager::init();
@@ -632,7 +632,7 @@ impl Process {
         *self.status.lock() = ProcessStatus::Zombie(term_status);
     }
 
-    pub fn exit_code(&self) -> Option<u32> {
+    pub fn exit_code(&self) -> Option<ExitCode> {
         match &*self.status.lock() {
             ProcessStatus::Runnable | ProcessStatus::Uninit => None,
             ProcessStatus::Zombie(term_status) => Some(term_status.as_u32()),
diff --git a/kernel/aster-nix/src/process/wait.rs b/kernel/aster-nix/src/process/wait.rs
index 7312bd93d..d086ec847 100644
--- a/kernel/aster-nix/src/process/wait.rs
+++ b/kernel/aster-nix/src/process/wait.rs
@@ -27,9 +27,9 @@ impl WaitOptions {
 pub fn wait_child_exit(
     child_filter: ProcessFilter,
     wait_options: WaitOptions,
-) -> Result<(Pid, ExitCode)> {
+) -> Result<Option<Arc<Process>>> {
     let current = current!();
-    let (pid, exit_code) = current.children_pauser().pause_until(|| {
+    let zombie_child = current.children_pauser().pause_until(|| {
         let unwaited_children = current
             .children()
             .lock()
@@ -54,29 +54,28 @@ pub fn wait_child_exit(
 
         if let Some(zombie_child) = zombie_child {
             let zombie_pid = zombie_child.pid();
-            let exit_code = zombie_child.exit_code().unwrap();
             if wait_options.contains(WaitOptions::WNOWAIT) {
                 // does not reap child, directly return
-                return Some(Ok((zombie_pid, exit_code)));
+                return Some(Ok(Some(zombie_child.clone())));
             } else {
-                let exit_code = reap_zombie_child(&current, zombie_pid);
-                return Some(Ok((zombie_pid, exit_code)));
+                reap_zombie_child(&current, zombie_pid);
+                return Some(Ok(Some(zombie_child.clone())));
             }
         }
 
         if wait_options.contains(WaitOptions::WNOHANG) {
-            return Some(Ok((0, 0)));
+            return Some(Ok(None));
         }
 
         // wait
         None
     })??;
 
-    Ok((pid, exit_code as _))
+    Ok(zombie_child)
 }
 
 /// Free zombie child with pid, returns the exit code of child process.
-fn reap_zombie_child(process: &Process, pid: Pid) -> u32 {
+fn reap_zombie_child(process: &Process, pid: Pid) -> ExitCode {
     let child_process = process.children().lock().remove(&pid).unwrap();
     assert!(child_process.is_zombie());
     child_process.root_vmar().destroy_all().unwrap();
diff --git a/kernel/aster-nix/src/syscall/wait4.rs b/kernel/aster-nix/src/syscall/wait4.rs
index 4e2b722f0..ba5fde989 100644
--- a/kernel/aster-nix/src/syscall/wait4.rs
+++ b/kernel/aster-nix/src/syscall/wait4.rs
@@ -1,13 +1,18 @@
 // SPDX-License-Identifier: MPL-2.0
 
-use super::SyscallReturn;
+use super::{getrusage::rusage_t, SyscallReturn};
 use crate::{
     prelude::*,
     process::{wait_child_exit, ProcessFilter, WaitOptions},
     util::write_val_to_user,
 };
 
-pub fn sys_wait4(wait_pid: u64, exit_status_ptr: u64, wait_options: u32) -> Result<SyscallReturn> {
+pub fn sys_wait4(
+    wait_pid: u64,
+    exit_status_ptr: u64,
+    wait_options: u32,
+    rusage_addr: Vaddr,
+) -> Result<SyscallReturn> {
     let wait_options = WaitOptions::from_bits(wait_options)
         .ok_or_else(|| Error::with_message(Errno::EINVAL, "unknown wait option"))?;
     debug!(
@@ -16,9 +21,26 @@ pub fn sys_wait4(wait_pid: u64, exit_status_ptr: u64, wait_options: u32) -> Resu
     );
     debug!("wait4 current pid = {}", current!().pid());
     let process_filter = ProcessFilter::from_id(wait_pid as _);
-    let (return_pid, exit_code) = wait_child_exit(process_filter, wait_options)?;
-    if return_pid != 0 && exit_status_ptr != 0 {
+
+    let waited_process = wait_child_exit(process_filter, wait_options)?;
+    let Some(process) = waited_process else {
+        return Ok(SyscallReturn::Return(0 as _));
+    };
+
+    let (return_pid, exit_code) = (process.pid(), process.exit_code().unwrap());
+    if exit_status_ptr != 0 {
         write_val_to_user(exit_status_ptr as _, &exit_code)?;
     }
+
+    if rusage_addr != 0 {
+        let rusage = rusage_t {
+            ru_utime: process.prof_clock().user_clock().read_time().into(),
+            ru_stime: process.prof_clock().kernel_clock().read_time().into(),
+            ..Default::default()
+        };
+
+        write_val_to_user(rusage_addr, &rusage)?;
+    }
+
     Ok(SyscallReturn::Return(return_pid as _))
 }
diff --git a/kernel/aster-nix/src/syscall/waitid.rs b/kernel/aster-nix/src/syscall/waitid.rs
index abd75dc23..34a1be36c 100644
--- a/kernel/aster-nix/src/syscall/waitid.rs
+++ b/kernel/aster-nix/src/syscall/waitid.rs
@@ -18,6 +18,7 @@ pub fn sys_waitid(
     // FIXME: what does infoq and rusage use for?
     let process_filter = ProcessFilter::from_which_and_id(which, upid);
     let wait_options = WaitOptions::from_bits(options as u32).expect("Unknown wait options");
-    let (exit_code, pid) = wait_child_exit(process_filter, wait_options)?;
+    let waited_process = wait_child_exit(process_filter, wait_options)?;
+    let pid = waited_process.map_or(0, |process| process.pid());
     Ok(SyscallReturn::Return(pid as _))
 }