diff --git a/os/src/config.rs b/os/src/config.rs
index 9a015bdc..0633c4da 100644
--- a/os/src/config.rs
+++ b/os/src/config.rs
@@ -1,3 +1,5 @@
+#[allow(unused)]
+
 pub const USER_STACK_SIZE: usize = 4096 * 2;
 pub const KERNEL_STACK_SIZE: usize = 4096 * 2;
 pub const KERNEL_HEAP_SIZE: usize = 0x20_0000;
diff --git a/os/src/drivers/block/mod.rs b/os/src/drivers/block/mod.rs
index abf20b61..f79b8b81 100644
--- a/os/src/drivers/block/mod.rs
+++ b/os/src/drivers/block/mod.rs
@@ -3,7 +3,6 @@ mod sdcard;
 
 use lazy_static::*;
 use alloc::sync::Arc;
-use core::any::Any;
 use easy_fs::BlockDevice;
 
 #[cfg(feature = "board_qemu")]
diff --git a/os/src/drivers/block/virtio_blk.rs b/os/src/drivers/block/virtio_blk.rs
index 2c045ed6..fde3428c 100644
--- a/os/src/drivers/block/virtio_blk.rs
+++ b/os/src/drivers/block/virtio_blk.rs
@@ -1,3 +1,4 @@
+
 use virtio_drivers::{VirtIOBlk, VirtIOHeader};
 use crate::mm::{
     PhysAddr,
@@ -15,6 +16,7 @@ use spin::Mutex;
 use alloc::vec::Vec;
 use lazy_static::*;
 
+#[allow(unused)]
 const VIRTIO0: usize = 0x10001000;
 
 pub struct VirtIOBlock(Mutex<VirtIOBlk<'static>>);
@@ -33,6 +35,7 @@ impl BlockDevice for VirtIOBlock {
 }
 
 impl VirtIOBlock {
+    #[allow(unused)]
     pub fn new() -> Self {
         Self(Mutex::new(VirtIOBlk::new(
             unsafe { &mut *(VIRTIO0 as *mut VirtIOHeader) }
diff --git a/os/src/syscall/process.rs b/os/src/syscall/process.rs
index ca4482b2..370ae9cb 100644
--- a/os/src/syscall/process.rs
+++ b/os/src/syscall/process.rs
@@ -11,7 +11,6 @@ use crate::mm::{
     translated_refmut,
 };
 use crate::fs::{
-    OSInode,
     open_file,
     OpenFlags,
 };
@@ -87,7 +86,7 @@ pub fn sys_waitpid(pid: isize, exit_code_ptr: *mut i32) -> isize {
         });
     if let Some((idx, _)) = pair {
         let child = inner.children.remove(idx);
-        // confirm that child will be deallocated after removing from children list
+        // confirm that child will be deallocated after being removed from children list
         assert_eq!(Arc::strong_count(&child), 1);
         let found_pid = child.getpid();
         // ++++ temporarily hold child lock