diff --git a/kernel/Cargo.lock b/kernel/Cargo.lock
index 7ca71d53..4848e5e3 100644
--- a/kernel/Cargo.lock
+++ b/kernel/Cargo.lock
@@ -402,12 +402,12 @@ dependencies = [
 [[package]]
 name = "rcore-fs"
 version = "0.1.0"
-source = "git+https://github.com/rcore-os/rcore-fs#d7a2006cc316c98b7050aec63a2770dd690a4a80"
+source = "git+https://github.com/rcore-os/rcore-fs#64d399fe664927f14853c22943a4bdeb34095f99"
 
 [[package]]
 name = "rcore-fs-sfs"
 version = "0.1.0"
-source = "git+https://github.com/rcore-os/rcore-fs#d7a2006cc316c98b7050aec63a2770dd690a4a80"
+source = "git+https://github.com/rcore-os/rcore-fs#64d399fe664927f14853c22943a4bdeb34095f99"
 dependencies = [
  "bitvec 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/kernel/src/fs/file.rs b/kernel/src/fs/file.rs
index dfb291fa..5e1b84f2 100644
--- a/kernel/src/fs/file.rs
+++ b/kernel/src/fs/file.rs
@@ -113,7 +113,7 @@ impl FileHandle {
         self.inode.poll()
     }
 
-    pub fn io_control(&self, cmd: u32, arg: u32) -> Result<()> {
+    pub fn io_control(&self, cmd: u32, arg: usize) -> Result<()> {
         self.inode.io_control(cmd, arg)
     }
 }
diff --git a/kernel/src/fs/file_like.rs b/kernel/src/fs/file_like.rs
index 47a3cc69..32c5cdcc 100644
--- a/kernel/src/fs/file_like.rs
+++ b/kernel/src/fs/file_like.rs
@@ -31,7 +31,7 @@ impl FileLike {
     }
     pub fn ioctl(&mut self, request: usize, arg1: usize, arg2: usize, arg3: usize) -> SysResult {
         match self {
-            FileLike::File(file) => file.io_control(request as u32, arg1 as u32)?,
+            FileLike::File(file) => file.io_control(request as u32, arg1)?,
             FileLike::Socket(socket) => {
                 socket.ioctl(request, arg1, arg2, arg3)?;
             }
diff --git a/kernel/src/fs/pipe.rs b/kernel/src/fs/pipe.rs
index c0c50eac..88073807 100644
--- a/kernel/src/fs/pipe.rs
+++ b/kernel/src/fs/pipe.rs
@@ -69,7 +69,7 @@ macro_rules! impl_inode {
         fn move_(&self, _old_name: &str, _target: &Arc<INode>, _new_name: &str) -> Result<()> { Err(FsError::NotDir) }
         fn find(&self, _name: &str) -> Result<Arc<INode>> { Err(FsError::NotDir) }
         fn get_entry(&self, _id: usize) -> Result<String> { Err(FsError::NotDir) }
-        fn io_control(&self, _cmd: u32, _data: u32) -> Result<()> { Err(FsError::NotSupported) }
+        fn io_control(&self, _cmd: u32, _data: usize) -> Result<()> { Err(FsError::NotSupported) }
         fn fs(&self) -> Arc<FileSystem> { unimplemented!() }
         fn as_any_ref(&self) -> &Any { self }
     };
diff --git a/kernel/src/fs/stdio.rs b/kernel/src/fs/stdio.rs
index 3fc60621..62500114 100644
--- a/kernel/src/fs/stdio.rs
+++ b/kernel/src/fs/stdio.rs
@@ -62,12 +62,20 @@ macro_rules! impl_inode {
         fn move_(&self, _old_name: &str, _target: &Arc<INode>, _new_name: &str) -> Result<()> { Err(FsError::NotDir) }
         fn find(&self, _name: &str) -> Result<Arc<INode>> { Err(FsError::NotDir) }
         fn get_entry(&self, _id: usize) -> Result<String> { Err(FsError::NotDir) }
-        fn io_control(&self, cmd: u32, data: u32) -> Result<()> {
+        fn io_control(&self, cmd: u32, data: usize) -> Result<()> {
             match cmd {
-                TCGETS | TIOCGWINSZ | TIOCGPGRP | TIOCSPGRP => {
+                TCGETS | TIOCGWINSZ | TIOCSPGRP => {
                     // pretend to be tty
                     Ok(())
                 },
+                TIOCGPGRP => {
+                    // pretend to be have a tty process group
+                    // TODO: verify pointer
+                    unsafe {
+                        *(data as *mut u32) = 0
+                    };
+                    Ok(())
+                }
                 _ => Err(FsError::NotSupported)
             }
         }
diff --git a/kernel/src/syscall/fs.rs b/kernel/src/syscall/fs.rs
index 7381d4b8..4ad87e73 100644
--- a/kernel/src/syscall/fs.rs
+++ b/kernel/src/syscall/fs.rs
@@ -72,9 +72,7 @@ pub fn sys_ppoll(ufds: *mut PollFd, nfds: usize, timeout: *const TimeSpec) -> Sy
         1 << 31 // infinity
     } else {
         proc.vm.check_read_ptr(timeout)?;
-        unsafe {
-            (*timeout).to_msec()
-        }
+        unsafe { (*timeout).to_msec() }
     };
     drop(proc);
 
diff --git a/kernel/src/syscall/proc.rs b/kernel/src/syscall/proc.rs
index 6f33cf83..81876289 100644
--- a/kernel/src/syscall/proc.rs
+++ b/kernel/src/syscall/proc.rs
@@ -24,11 +24,12 @@ pub fn sys_clone(
     newtls: usize,
     tf: &TrapFrame,
 ) -> SysResult {
+    let clone_flags = CloneFlags::from_bits_truncate(flags);
     info!(
-        "clone: flags: {:#x}, newsp: {:#x}, parent_tid: {:?}, child_tid: {:?}, newtls: {:#x}",
-        flags, newsp, parent_tid, child_tid, newtls
+        "clone: flags: {:?}, newsp: {:#x}, parent_tid: {:?}, child_tid: {:?}, newtls: {:#x}",
+        clone_flags, newsp, parent_tid, child_tid, newtls
     );
-    if flags == 0x4111 {
+    if flags == 0x4111 || flags == 0x11 {
         warn!("sys_clone is calling sys_fork instead, ignoring other args");
         return sys_fork(tf);
     }
@@ -317,3 +318,30 @@ pub fn sys_set_priority(priority: usize) -> SysResult {
     processor().manager().set_priority(pid, priority as u8);
     Ok(0)
 }
+
+bitflags! {
+    pub struct CloneFlags: usize {
+        const CSIGNAL = 0x000000ff;
+        const VM = 0x0000100;
+        const FS = 0x0000200;
+        const FILES = 0x0000400;
+        const SIGHAND = 0x0000800;
+        const PTRACE = 0x0002000;
+        const VFORK = 0x0004000;
+        const PARENT = 0x0008000;
+        const SYSVSEM = 0x0008000;
+        const SETTLS = 0x0008000;
+        const PARENT_SETTID = 0x0010000;
+        const CHILD_CLEARTID = 0x0020000;
+        const DETACHED = 0x0040000;
+        const UNTRACED = 0x0080000;
+        const CHILD_SETTID = 0x0100000;
+        const NEWCGROUP = 0x0200000;
+        const NEWUTS = 0x0400000;
+        const NEWIPC = 0x0800000;
+        const NEWUSER = 0x1000000;
+        const NEWPID = 0x2000000;
+        const NEWNET = 0x4000000;
+        const IO = 0x8000000;
+    }
+}
diff --git a/user b/user
index fdaa1be8..8dbc0edb 160000
--- a/user
+++ b/user
@@ -1 +1 @@
-Subproject commit fdaa1be8635944d88ff128da13bf0464f7ce2eb6
+Subproject commit 8dbc0edb935a62d748aaac39258d4a985de0ae17