diff --git a/src/services/libs/jinux-std/src/process/mod.rs b/src/services/libs/jinux-std/src/process/mod.rs
index 755cdff43..49a2538fb 100644
--- a/src/services/libs/jinux-std/src/process/mod.rs
+++ b/src/services/libs/jinux-std/src/process/mod.rs
@@ -9,6 +9,7 @@ use self::signal::constants::SIGCHLD;
 use self::signal::sig_disposition::SigDispositions;
 use self::signal::sig_queues::SigQueues;
 use self::signal::signals::kernel::KernelSignal;
+use self::signal::signals::Signal;
 use self::status::ProcessStatus;
 use crate::fs::file_table::FileTable;
 use crate::fs::fs_resolver::FsResolver;
@@ -379,6 +380,12 @@ impl Process {
     pub fn sig_queues(&self) -> &Mutex<SigQueues> {
         &self.sig_queues
     }
+
+    pub fn enqueue_signal(&self, signal: Box<dyn Signal>) {
+        if !self.status().lock().is_zombie() {
+            self.sig_queues.lock().enqueue(signal);
+        }
+    }
 }
 
 /// Get the init process
diff --git a/src/services/libs/jinux-std/src/process/process_group.rs b/src/services/libs/jinux-std/src/process/process_group.rs
index cb9676b34..f469e2e3c 100644
--- a/src/services/libs/jinux-std/src/process/process_group.rs
+++ b/src/services/libs/jinux-std/src/process/process_group.rs
@@ -1,4 +1,8 @@
-use super::{process_table, signal::signals::kernel::KernelSignal, Pgid, Pid, Process};
+use super::{
+    process_table,
+    signal::signals::{kernel::KernelSignal, user::UserSignal},
+    Pgid, Pid, Process,
+};
 use crate::prelude::*;
 
 pub struct ProcessGroup {
@@ -76,10 +80,14 @@ impl ProcessGroup {
     /// send kernel signal to all processes in the group
     pub fn kernel_signal(&self, signal: KernelSignal) {
         for (_, process) in &self.inner.lock().processes {
-            process
-                .sig_queues()
-                .lock()
-                .enqueue(Box::new(signal.clone()));
+            process.enqueue_signal(Box::new(signal.clone()));
+        }
+    }
+
+    /// send user signal to all processes in the group
+    pub fn user_signal(&self, signal: UserSignal) {
+        for (_, process) in &self.inner.lock().processes {
+            process.enqueue_signal(Box::new(signal.clone()));
         }
     }
 }
diff --git a/src/services/libs/jinux-std/src/process/signal/mod.rs b/src/services/libs/jinux-std/src/process/signal/mod.rs
index 3c2913e44..caa739bfa 100644
--- a/src/services/libs/jinux-std/src/process/signal/mod.rs
+++ b/src/services/libs/jinux-std/src/process/signal/mod.rs
@@ -85,8 +85,6 @@ pub fn handle_pending_signal(context: &mut CpuContext) -> Result<()> {
                         let mut status = current_thread.status().lock();
                         if status.is_running() {
                             status.set_stopped();
-                        } else {
-                            panic!("Try to suspend a not running process.")
                         }
                         drop(status);
                     }
@@ -94,8 +92,6 @@ pub fn handle_pending_signal(context: &mut CpuContext) -> Result<()> {
                         let mut status = current_thread.status().lock();
                         if status.is_stopped() {
                             status.set_running();
-                        } else {
-                            panic!("Try to continue a not suspended process.")
                         }
                         drop(status);
                     }
diff --git a/src/services/libs/jinux-std/src/syscall/kill.rs b/src/services/libs/jinux-std/src/syscall/kill.rs
index e5b234bc1..a175894be 100644
--- a/src/services/libs/jinux-std/src/syscall/kill.rs
+++ b/src/services/libs/jinux-std/src/syscall/kill.rs
@@ -1,7 +1,7 @@
 use crate::{log_syscall_entry, prelude::*};
 
+use crate::process::process_table;
 use crate::process::signal::signals::user::{UserSignal, UserSignalKind};
-use crate::process::{process_table, Process};
 use crate::{
     process::{process_filter::ProcessFilter, signal::sig_num::SigNum},
     syscall::SYS_KILL,
@@ -21,41 +21,32 @@ pub fn sys_kill(process_filter: u64, sig_num: u64) -> Result<SyscallReturn> {
     Ok(SyscallReturn::Return(0))
 }
 
-pub fn do_sys_kill(process_filter: ProcessFilter, sig_num: SigNum) -> Result<()> {
+pub fn do_sys_kill(filter: ProcessFilter, sig_num: SigNum) -> Result<()> {
     let current = current!();
     let pid = current.pid();
     // FIXME: use the correct uid
     let uid = 0;
-    let processes = get_processes(&process_filter)?;
-    for process in processes.iter() {
-        if process.status().lock().is_zombie() {
-            continue;
+    let signal = UserSignal::new(sig_num, UserSignalKind::Kill, pid, uid);
+    match filter {
+        ProcessFilter::Any => {
+            for process in process_table::get_all_processes() {
+                process.enqueue_signal(Box::new(signal.clone()));
+            }
+        }
+        ProcessFilter::WithPid(pid) => {
+            if let Some(process) = process_table::pid_to_process(pid) {
+                process.enqueue_signal(Box::new(signal));
+            } else {
+                return_errno_with_message!(Errno::ESRCH, "No such process in process table");
+            }
+        }
+        ProcessFilter::WithPgid(pgid) => {
+            if let Some(process_group) = process_table::pgid_to_process_group(pgid) {
+                process_group.user_signal(signal);
+            } else {
+                return_errno_with_message!(Errno::ESRCH, "No such process group in process table");
+            }
         }
-
-        let signal = Box::new(UserSignal::new(sig_num, UserSignalKind::Kill, pid, uid));
-        let sig_queues = process.sig_queues();
-        sig_queues.lock().enqueue(signal);
     }
     Ok(())
 }
-
-fn get_processes(filter: &ProcessFilter) -> Result<Vec<Arc<Process>>> {
-    let processes = match filter {
-        ProcessFilter::Any => {
-            let mut processes = process_table::get_all_processes();
-            processes.retain(|process| process.pid() != 0);
-            processes
-        }
-        ProcessFilter::WithPid(pid) => {
-            let process = process_table::pid_to_process(*pid);
-            match process {
-                None => {
-                    return_errno_with_message!(Errno::ESRCH, "No such process in process table")
-                }
-                Some(process) => vec![process],
-            }
-        }
-        ProcessFilter::WithPgid(_) => todo!(),
-    };
-    Ok(processes)
-}