diff --git a/kernel/src/fs/file.rs b/kernel/src/fs/file.rs
index 3979c4d..d41c5a5 100644
--- a/kernel/src/fs/file.rs
+++ b/kernel/src/fs/file.rs
@@ -1,6 +1,7 @@
 //! File handle for process
 
 use alloc::{string::String, sync::Arc};
+use core::fmt;
 
 use rcore_fs::vfs::{FsError, INode, Metadata, PollStatus, Result};
 
@@ -9,6 +10,10 @@ pub struct FileHandle {
     inode: Arc<INode>,
     offset: u64,
     options: OpenOptions,
+
+    // for debugging
+    #[cfg(debug_assertions)]
+    path: String,
 }
 
 #[derive(Debug, Clone)]
@@ -28,11 +33,29 @@ pub enum SeekFrom {
 
 impl FileHandle {
     pub fn new(inode: Arc<INode>, options: OpenOptions) -> Self {
-        FileHandle {
+        #[cfg(debug_assertions)]
+        return FileHandle {
             inode,
             offset: 0,
             options,
-        }
+            path: String::from("unknown"),
+        };
+        #[cfg(not(debug_assertions))]
+        return FileHandle {
+            inode,
+            offset: 0,
+            options,
+        };
+    }
+
+    #[cfg(debug_assertions)]
+    pub fn set_path(&mut self, path: &str) {
+        self.path = String::from(path);
+    }
+
+    #[cfg(not(debug_assertions))]
+    pub fn set_path(&mut self, _path: &str) {
+        unreachable!()
     }
 
     pub fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
@@ -121,3 +144,22 @@ impl FileHandle {
         self.inode.clone()
     }
 }
+
+impl fmt::Debug for FileHandle {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // for debugging
+        #[cfg(debug_assertions)]
+        return f
+            .debug_struct("FileHandle")
+            .field("offset", &self.offset)
+            .field("options", &self.options)
+            .field("path", &self.path)
+            .finish();
+        #[cfg(not(debug_assertions))]
+        return f
+            .debug_struct("FileHandle")
+            .field("offset", &self.offset)
+            .field("options", &self.options)
+            .finish();
+    }
+}
diff --git a/kernel/src/fs/file_like.rs b/kernel/src/fs/file_like.rs
index 32c5cdc..c8730eb 100644
--- a/kernel/src/fs/file_like.rs
+++ b/kernel/src/fs/file_like.rs
@@ -53,7 +53,7 @@ impl FileLike {
 impl fmt::Debug for FileLike {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            FileLike::File(_) => write!(f, "File"),
+            FileLike::File(file) => write!(f, "File {:?}", file),
             FileLike::Socket(_) => write!(f, "Socket"),
         }
     }
diff --git a/kernel/src/memory.rs b/kernel/src/memory.rs
index f34354f..6ee97b9 100644
--- a/kernel/src/memory.rs
+++ b/kernel/src/memory.rs
@@ -157,7 +157,7 @@ pub fn enlarge_heap(heap: &mut Heap) {
         let page = alloc_frame().unwrap();
         let va = KERNEL_OFFSET + 0xe0000000 + page;
         if addr_len > 0 {
-            let (ref mut addr, ref mut len) = addrs[addr_len-1];
+            let (ref mut addr, ref mut len) = addrs[addr_len - 1];
             if *addr - PAGE_SIZE == va {
                 *len += PAGE_SIZE;
                 *addr -= PAGE_SIZE;
diff --git a/kernel/src/syscall/fs.rs b/kernel/src/syscall/fs.rs
index efa0852..de38f95 100644
--- a/kernel/src/syscall/fs.rs
+++ b/kernel/src/syscall/fs.rs
@@ -273,7 +273,14 @@ pub fn sys_openat(dir_fd: usize, path: *const u8, flags: usize, mode: usize) ->
         proc.lookup_inode_at(dir_fd, &path, true)?
     };
 
-    let file = FileHandle::new(inode, flags.to_options());
+    let mut file = FileHandle::new(inode, flags.to_options());
+
+    // for debugging
+    if cfg!(debug_assertions) {
+        file.set_path(&path);
+        debug!("files before open {:#?}", proc.files);
+    }
+
     let fd = proc.add_file(FileLike::File(file));
     Ok(fd)
 }
@@ -281,6 +288,12 @@ pub fn sys_openat(dir_fd: usize, path: *const u8, flags: usize, mode: usize) ->
 pub fn sys_close(fd: usize) -> SysResult {
     info!("close: fd: {:?}", fd);
     let mut proc = process();
+
+    // for debugging
+    if cfg!(debug_assertions) {
+        debug!("files before close {:#?}", proc.files);
+    }
+
     proc.files.remove(&fd).ok_or(SysError::EBADF)?;
     Ok(0)
 }