diff --git a/kernel/Cargo.toml b/kernel/Cargo.toml
index f5dbb60..6eeff65 100644
--- a/kernel/Cargo.toml
+++ b/kernel/Cargo.toml
@@ -32,7 +32,7 @@ bit_field = "0.10.1"
 lose-net-stack = { git = "https://github.com/byte-os/lose-net-stack", rev = "bb99460", features = ["log"]}
 # lose-net-stack = { path = "../../lose-net-stack", features = ["log"]}
 vfscore = { git = "https://github.com/Byte-OS/vfscore.git" }
-async-recursion = "1.0.4"
+async-recursion = "1.1.0"
 futures-lite = { version = "1.13.0", default-features = false, features=["alloc"] }
 # backtrace = { path = "../crates/backtrace" }
 hashbrown = "0.14"
diff --git a/kernel/build.rs b/kernel/build.rs
index ff2bff4..5f03f2d 100644
--- a/kernel/build.rs
+++ b/kernel/build.rs
@@ -11,11 +11,12 @@ macro_rules! display {
 
 // write module config to file.
 fn write_module_config(driver_list: Vec<String>) {
-    let manifest_path =
-        PathBuf::from(env::var("OUT_DIR").expect("can't find manifest dir"));
+    let manifest_path = PathBuf::from(env::var("OUT_DIR").expect("can't find manifest dir"));
     let mut module_file_content = String::new();
     driver_list.into_iter().for_each(|module| {
-        if module == "" { return };
+        if module == "" {
+            return;
+        };
         module_file_content.push_str(&format!("extern crate {};\n", module.replace("-", "_")))
     });
     fs::write(manifest_path.join("drivers.rs"), module_file_content)
@@ -23,7 +24,8 @@ fn write_module_config(driver_list: Vec<String>) {
 }
 
 fn main() {
-    let drivers = std::env::var("CARGO_CFG_DRIVER").unwrap_or(String::from(""))
+    let drivers = std::env::var("CARGO_CFG_DRIVER")
+        .unwrap_or(String::from(""))
         .split(",")
         .map(|x| x.trim().to_owned())
         .collect();
diff --git a/kernel/src/syscall/mod.rs b/kernel/src/syscall/mod.rs
index b0aee79..e0f039f 100644
--- a/kernel/src/syscall/mod.rs
+++ b/kernel/src/syscall/mod.rs
@@ -295,8 +295,8 @@ impl UserTaskContainer {
                     args[0] as _,
                     args[1] as _,
                     args[2] as _,
-                    args[3] as _,
-                    args[4] as _,
+                    args[3].into(),
+                    args[4].into(),
                 )
                 .await
             }
diff --git a/kernel/src/syscall/socket.rs b/kernel/src/syscall/socket.rs
index 1da3df1..063f7a7 100644
--- a/kernel/src/syscall/socket.rs
+++ b/kernel/src/syscall/socket.rs
@@ -375,29 +375,27 @@ impl UserTaskContainer {
         socket: usize,
         level: usize,
         optname: usize,
-        optval: *mut u32,
-        optlen: *mut u32,
+        optval: UserRef<u32>,
+        optlen: UserRef<u32>,
     ) -> SysResult {
         debug!("[task {}] sys_getsockopt @ socket: {:#x}, level: {:#x}, optname: {:#x}, optval: {:#x?}, optlen: {:#x?}", 
         self.tid, socket, level, optname, optval, optlen);
-        unsafe {
-            let optval = optval.as_mut().unwrap();
-            let _optlen = optlen.as_mut().unwrap();
-
-            match optname {
-                // send buffer
-                0x7 => *optval = 32000,
-                // recv buffer
-                0x8 => *optval = 32000,
-                0x2 => *optval = 2000,
-                // getsockopt
-                0x4 => return Err(LinuxError::EPERM),
-                _ => {
-                    // *optval = 2000;
-                }
+        let optval = optval.get_mut();
+        let _optlen = optlen.get_mut();
+
+        match optname {
+            // send buffer
+            0x7 => *optval = 32000,
+            // recv buffer
+            0x8 => *optval = 32000,
+            0x2 => *optval = 2000,
+            // getsockopt
+            0x4 => return Err(LinuxError::EPERM),
+            _ => {
+                // *optval = 2000;
             }
-            // debug!("ptr value: {:?}", optval);
         }
+        // debug!("ptr value: {:?}", optval);
         Ok(0)
     }
 
diff --git a/kernel/src/syscall/task.rs b/kernel/src/syscall/task.rs
index 9937adf..9843d04 100644
--- a/kernel/src/syscall/task.rs
+++ b/kernel/src/syscall/task.rs
@@ -186,15 +186,14 @@ pub fn cache_task_template(path: &str) -> Result<(), LinuxError> {
     Ok(())
 }
 
-#[async_recursion(?Send)]
-pub async fn exec_with_process<'a>(
+#[async_recursion(Sync)]
+pub async fn exec_with_process(
     task: Arc<UserTask>,
-    path: &'a str,
-    args: Vec<&'a str>,
-    envp: Vec<&'a str>,
+    path: String,
+    args: Vec<String>,
+    envp: Vec<String>,
 ) -> Result<Arc<UserTask>, LinuxError> {
     // copy args, avoid free before pushing.
-    let args: Vec<String> = args.into_iter().map(|x| String::from(x)).collect();
     let path = String::from(path);
     let user_task = task.clone();
     user_task.pcb.lock().memset.clear();
@@ -247,9 +246,9 @@ pub async fn exec_with_process<'a>(
         let elf = if let Ok(elf) = xmas_elf::ElfFile::new(&buffer) {
             elf
         } else {
-            let mut new_args = vec!["busybox", "sh"];
-            args.iter().for_each(|x| new_args.push(x));
-            return exec_with_process(task, "busybox", new_args, envp).await;
+            let mut new_args = vec!["busybox".to_string(), "sh".to_string()];
+            args.iter().for_each(|x| new_args.push(x.clone()));
+            return exec_with_process(task, String::from("busybox"), new_args, envp).await;
         };
         let elf_header = elf.header;
 
@@ -270,10 +269,9 @@ pub async fn exec_with_process<'a>(
         if let Some(header) = header {
             if let Ok(SegmentData::Undefined(_data)) = header.get_data(&elf) {
                 drop(frame_ppn);
-                let lib_path = "libc.so";
-                let mut new_args = vec![lib_path, &path];
-                args[1..].iter().for_each(|x| new_args.push(x));
-                return exec_with_process(task, lib_path, new_args, envp).await;
+                let mut new_args = vec![String::from("libc.so")];
+                new_args.extend(args);
+                return exec_with_process(task, new_args[0].clone(), new_args, envp).await;
             }
         }
 
@@ -346,6 +344,7 @@ pub async fn exec_with_process<'a>(
                 assert_eq!(&buffer[offset..offset + file_size], page_space);
             });
 
+        // relocate data
         if base > 0 {
             relocated_arr.into_iter().for_each(|(addr, value)| unsafe {
                 (addr as *mut usize).write_volatile(value);
@@ -407,13 +406,13 @@ impl UserTaskContainer {
         let args = args
             .slice_until_valid(|x| x.is_valid())
             .into_iter()
-            .map(|x| x.get_cstr().unwrap())
+            .map(|x| x.get_cstr().unwrap().to_string())
             .collect();
         debug!("test1: envp: {:?}", envp);
-        let envp: Vec<&str> = envp
+        let envp: Vec<String> = envp
             .slice_until_valid(|x| x.is_valid())
             .into_iter()
-            .map(|x| x.get_cstr().unwrap())
+            .map(|x| x.get_cstr().unwrap().to_string())
             .collect();
         debug!(
             "sys_execve @ filename: {} args: {:?}: envp: {:?}",
@@ -430,7 +429,7 @@ impl UserTaskContainer {
             return Ok(0);
         }
         let _exec_file = FileItem::fs_open(filename, OpenFlags::O_RDONLY).map_err(from_vfs)?;
-        exec_with_process(self.task.clone(), filename, args, envp).await?;
+        exec_with_process(self.task.clone(), filename.to_string(), args, envp).await?;
         self.task.before_run();
         Ok(0)
     }
diff --git a/kernel/src/tasks/mod.rs b/kernel/src/tasks/mod.rs
index 64c0bff..99d5d2a 100644
--- a/kernel/src/tasks/mod.rs
+++ b/kernel/src/tasks/mod.rs
@@ -1,3 +1,4 @@
+use alloc::string::String;
 use alloc::sync::Weak;
 use alloc::{sync::Arc, vec::Vec};
 use devices::get_net_device;
@@ -100,9 +101,14 @@ pub async fn add_user_task(filename: &str, args: Vec<&str>, envp: Vec<&str>) ->
     let task = UserTask::new(user_entry(), Weak::new(), initproc::USER_WORK_DIR);
 
     task.before_run();
-    exec_with_process(task.clone(), filename, args, envp)
-        .await
-        .expect("can't add task to excutor");
+    exec_with_process(
+        task.clone(),
+        String::from(filename),
+        args.into_iter().map(String::from).collect(),
+        envp.into_iter().map(String::from).collect(),
+    )
+    .await
+    .expect("can't add task to excutor");
     thread::spawn(task.clone());
     curr_task.before_run();
 
diff --git a/kernel/src/tasks/task.rs b/kernel/src/tasks/task.rs
index f5b3447..5ace496 100644
--- a/kernel/src/tasks/task.rs
+++ b/kernel/src/tasks/task.rs
@@ -12,7 +12,7 @@ use arch::{
     {TrapFrame, TrapFrameArgs, PAGE_SIZE},
 };
 use executor::{
-    task_id_alloc, thread, AsyncTask, DowncastTask, TaskFutureItem, TaskId, FUTURE_LIST,
+    task_id_alloc, thread, AsyncTask, DowncastTask, TaskId, FUTURE_LIST,
 };
 use frame_allocator::{ceil_div, frame_alloc_much, FrameTracker};
 use fs::File;
@@ -49,13 +49,13 @@ impl Drop for KernelTask {
 }
 
 impl KernelTask {
-    pub fn new(future: impl Future<Output = ()> + 'static) -> Arc<Self> {
+    pub fn new(future: impl Future<Output = ()> + Send + 'static) -> Arc<Self> {
         let task_id = task_id_alloc();
         let memset = vec![];
 
         FUTURE_LIST
             .lock()
-            .insert(task_id, TaskFutureItem(Box::pin(kernel_entry(future))));
+            .insert(task_id, Box::pin(kernel_entry(future)));
 
         Arc::new(Self {
             page_table: Arc::new(PageTableWrapper::alloc()),
@@ -126,7 +126,7 @@ impl Drop for UserTask {
 
 impl UserTask {
     pub fn new(
-        future: impl Future<Output = ()> + 'static,
+        future: impl Future<Output = ()> + Send + 'static,
         parent: Weak<UserTask>,
         work_dir: &str,
     ) -> Arc<Self> {
@@ -136,7 +136,7 @@ impl UserTask {
 
         FUTURE_LIST
             .lock()
-            .insert(task_id, TaskFutureItem(Box::pin(future)));
+            .insert(task_id, Box::pin(future));
 
         let inner = ProcessControlBlock {
             memset,
@@ -392,7 +392,10 @@ impl UserTask {
     }
 
     #[inline]
-    pub fn cow_fork(self: Arc<Self>, future: impl Future<Output = ()> + 'static) -> Arc<Self> {
+    pub fn cow_fork(
+        self: Arc<Self>,
+        future: impl Future<Output = ()> + Send + 'static,
+    ) -> Arc<Self> {
         // Give the frame_tracker in the memset a type.
         // it will contains the frame used for page mapping、
         // mmap or text section.
@@ -443,7 +446,10 @@ impl UserTask {
     }
 
     #[inline]
-    pub fn thread_clone(self: Arc<Self>, future: impl Future<Output = ()> + 'static) -> Arc<Self> {
+    pub fn thread_clone(
+        self: Arc<Self>,
+        future: impl Future<Output = ()> + Send + 'static,
+    ) -> Arc<Self> {
         // Give the frame_tracker in the memset a type.
         // it will contains the frame used for page mapping、
         // mmap or text section.
@@ -479,7 +485,7 @@ impl UserTask {
 
         FUTURE_LIST
             .lock()
-            .insert(task_id, TaskFutureItem(Box::pin(future)));
+            .insert(task_id, Box::pin(future));
 
         thread::spawn(new_task.clone());
         new_task
diff --git a/kernel/src/user/entry.rs b/kernel/src/user/entry.rs
index 428cc32..89b372c 100644
--- a/kernel/src/user/entry.rs
+++ b/kernel/src/user/entry.rs
@@ -1,4 +1,6 @@
+use alloc::boxed::Box;
 use arch::{kernel_page_table, TrapFrame, TrapFrameArgs};
+use async_recursion::async_recursion;
 use executor::{yield_now, AsyncTask};
 use futures_lite::future;
 use hal::TimeVal;
@@ -32,42 +34,42 @@ impl UserTaskContainer {
         }
     }
 
-    pub async fn entry_point(&mut self, cx_ref: &mut TrapFrame) {
-        let mut times = 0;
-
-        let check_signal = async || {
-            loop {
-                let sig_mask = self.task.tcb.read().sigmask;
-                let signal = self
-                    .task
-                    .tcb
-                    .read()
-                    .signal
-                    .clone()
-                    .mask(sig_mask)
-                    .try_get_signal();
-                if let Some(signal) = signal {
-                    debug!("mask: {:?}", sig_mask);
-                    self.handle_signal(signal.clone()).await;
-                    let mut tcb = self.task.tcb.write();
-                    tcb.signal.remove_signal(signal.clone());
-                    // check if it is a real time signal
-                    if let Some(index) = signal.real_time_index()
-                        && tcb.signal_queue[index] > 0
-                    {
-                        tcb.signal.add_signal(signal.clone());
-                        tcb.signal_queue[index] -= 1;
-                    }
-                } else {
-                    break;
+    pub async fn check_signal(&self) {
+        loop {
+            let sig_mask = self.task.tcb.read().sigmask;
+            let signal = self
+                .task
+                .tcb
+                .read()
+                .signal
+                .clone()
+                .mask(sig_mask)
+                .try_get_signal();
+            if let Some(signal) = signal {
+                debug!("mask: {:?}", sig_mask);
+                self.handle_signal(signal.clone()).await;
+                let mut tcb = self.task.tcb.write();
+                tcb.signal.remove_signal(signal.clone());
+                // check if it is a real time signal
+                if let Some(index) = signal.real_time_index()
+                    && tcb.signal_queue[index] > 0
+                {
+                    tcb.signal.add_signal(signal.clone());
+                    tcb.signal_queue[index] -= 1;
                 }
+            } else {
+                break;
             }
-        };
+        }
+    }
+
+    pub async fn entry_point(&mut self, cx_ref: &mut TrapFrame) {
+        let mut times: i32 = 0;
 
         loop {
             self.check_timer();
 
-            check_signal().await;
+            self.check_signal().await;
 
             // check for task exit status.
             if let Some(exit_code) = self.check_thread_exit() {
@@ -87,7 +89,7 @@ impl UserTaskContainer {
 
             let res = future::or(self.handle_syscall(cx_ref), async {
                 loop {
-                    check_signal().await;
+                    self.check_signal().await;
 
                     if let Some(_exit_code) = self.check_thread_exit() {
                         return UserTaskControlFlow::Break;
@@ -122,15 +124,10 @@ impl UserTaskContainer {
     }
 }
 
+#[async_recursion(Sync)]
 pub async fn user_entry() {
     let task = current_user_task();
     let cx_ref = task.force_cx_ref();
     let tid = task.get_task_id();
-    UserTaskContainer {
-        task,
-        tid,
-        store_frames: vec![],
-    }
-    .entry_point(cx_ref)
-    .await;
+    UserTaskContainer { task, tid }.entry_point(cx_ref).await;
 }
diff --git a/kernel/src/user/mod.rs b/kernel/src/user/mod.rs
index a6d5e51..dd903d4 100644
--- a/kernel/src/user/mod.rs
+++ b/kernel/src/user/mod.rs
@@ -1,12 +1,9 @@
-use core::pin::Pin;
-
 use ::signal::SignalFlags;
-use alloc::{boxed::Box, sync::Arc, vec::Vec};
+use alloc::sync::Arc;
 use arch::addr::VirtPage;
 use arch::{pagetable::MappingFlags, run_user_task, time::Time, TrapFrame, TrapFrameArgs};
 use executor::{AsyncTask, TaskId};
 use frame_allocator::frame_alloc;
-use futures_lite::Future;
 use log::{debug, warn};
 
 use crate::tasks::{MapTrack, MemType, UserTask};
@@ -22,10 +19,6 @@ pub mod socket_pair;
 pub struct UserTaskContainer {
     pub task: Arc<UserTask>,
     pub tid: TaskId,
-    pub store_frames: Vec<(
-        TrapFrame,
-        Pin<Box<dyn Future<Output = UserTaskControlFlow>>>,
-    )>,
 }
 
 /// Copy on write.