diff --git a/os/src/drivers/mod.rs b/os/src/drivers/mod.rs
index e16c51ea..605397dd 100644
--- a/os/src/drivers/mod.rs
+++ b/os/src/drivers/mod.rs
@@ -8,7 +8,6 @@ pub mod plic;
 
 pub use block::BLOCK_DEVICE;
 pub use bus::*;
-pub use chardev::UART;
 pub use gpu::*;
 pub use input::*;
 pub use net::*;
diff --git a/os/src/fs/mod.rs b/os/src/fs/mod.rs
index 221d68b3..cbde739d 100644
--- a/os/src/fs/mod.rs
+++ b/os/src/fs/mod.rs
@@ -11,6 +11,6 @@ pub trait File: Send + Sync {
     fn write(&self, buf: UserBuffer) -> usize;
 }
 
-pub use inode::{list_apps, open_file, OSInode, OpenFlags, ROOT_INODE};
-pub use pipe::{make_pipe, Pipe};
+pub use inode::{list_apps, open_file, OpenFlags};
+pub use pipe::make_pipe;
 pub use stdio::{Stdin, Stdout};
diff --git a/os/src/mm/mod.rs b/os/src/mm/mod.rs
index 574cea02..642d0b7d 100644
--- a/os/src/mm/mod.rs
+++ b/os/src/mm/mod.rs
@@ -7,12 +7,11 @@ mod page_table;
 pub use address::VPNRange;
 pub use address::{PhysAddr, PhysPageNum, StepByOne, VirtAddr, VirtPageNum};
 pub use frame_allocator::{frame_alloc, frame_alloc_more, frame_dealloc, FrameTracker};
-pub use memory_set::remap_test;
 pub use memory_set::{kernel_token, MapArea, MapPermission, MapType, MemorySet, KERNEL_SPACE};
 use page_table::PTEFlags;
 pub use page_table::{
     translated_byte_buffer, translated_ref, translated_refmut, translated_str, PageTable,
-    PageTableEntry, UserBuffer, UserBufferIterator,
+    PageTableEntry, UserBuffer,
 };
 
 pub fn init() {