diff --git a/README.md b/README.md
index 767cb147..2df01b07 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,7 @@ Here we manually compile and install Qemu 7.0.0. For example, on Ubuntu 18.04:
 # install dependency packages
 $ sudo apt install autoconf automake autotools-dev curl libmpc-dev libmpfr-dev libgmp-dev \
               gawk build-essential bison flex texinfo gperf libtool patchutils bc \
-              zlib1g-dev libexpat-dev pkg-config  libglib2.0-dev libpixman-1-dev git tmux python3 python3-pip
+              zlib1g-dev libexpat-dev pkg-config  libglib2.0-dev libpixman-1-dev git tmux python3 python3-pip ninja-build
 # download Qemu source code
 $ wget https://download.qemu.org/qemu-7.0.0.tar.xz
 # extract to qemu-7.0.0/
@@ -64,9 +64,7 @@ $ make -j$(nproc)
 Then, add following contents to `~/.bashrc`(please adjust these paths according to your environment):
 
 ```
-export PATH=$PATH:/home/shinbokuow/Downloads/built/qemu-7.0.0
-export PATH=$PATH:/home/shinbokuow/Downloads/built/qemu-7.0.0/riscv64-softmmu
-export PATH=$PATH:/home/shinbokuow/Downloads/built/qemu-7.0.0/riscv64-linux-user
+export PATH=$PATH:/path/to/qemu-7.0.0/build
 ```
 
 Finally, update the current shell:
diff --git a/easy-fs-fuse/Cargo.toml b/easy-fs-fuse/Cargo.toml
index 5c5e68d5..d8d4e7fe 100644
--- a/easy-fs-fuse/Cargo.toml
+++ b/easy-fs-fuse/Cargo.toml
@@ -13,4 +13,4 @@ rand = "0.8.0"
 
 # [features]
 # board_qemu = []
-# board_k210 = []
\ No newline at end of file
+# board_k210 = []
diff --git a/figures/logo.png b/figures/logo.png
new file mode 100644
index 00000000..84af0817
Binary files /dev/null and b/figures/logo.png differ
diff --git a/os/src/drivers/block/virtio_blk.rs b/os/src/drivers/block/virtio_blk.rs
index fb89084d..34a93e0d 100644
--- a/os/src/drivers/block/virtio_blk.rs
+++ b/os/src/drivers/block/virtio_blk.rs
@@ -5,6 +5,7 @@ use crate::task::schedule;
 use crate::DEV_NON_BLOCKING_ACCESS;
 use alloc::collections::BTreeMap;
 use virtio_drivers::{BlkResp, RespStatus, VirtIOBlk, VirtIOHeader};
+use crate::drivers::bus::virtio::VirtioHal;
 
 #[allow(unused)]
 const VIRTIO0: usize = 0x10008000;
diff --git a/os/src/drivers/gpu/mod.rs b/os/src/drivers/gpu/mod.rs
index 759633ff..b1281e1d 100644
--- a/os/src/drivers/gpu/mod.rs
+++ b/os/src/drivers/gpu/mod.rs
@@ -5,6 +5,7 @@ use core::any::Any;
 use embedded_graphics::pixelcolor::Rgb888;
 use tinybmp::Bmp;
 use virtio_drivers::{VirtIOGpu, VirtIOHeader};
+use crate::drivers::bus::virtio::VirtioHal;
 const VIRTIO7: usize = 0x10007000;
 pub trait GpuDevice: Send + Sync + Any {
     fn update_cursor(&self);
diff --git a/os/src/drivers/mod.rs b/os/src/drivers/mod.rs
index e4f41724..e16c51ea 100644
--- a/os/src/drivers/mod.rs
+++ b/os/src/drivers/mod.rs
@@ -11,4 +11,4 @@ pub use bus::*;
 pub use chardev::UART;
 pub use gpu::*;
 pub use input::*;
-pub use net::*;
\ No newline at end of file
+pub use net::*;
diff --git a/os/src/task/id.rs b/os/src/task/id.rs
index c1771813..23ddf7b5 100644
--- a/os/src/task/id.rs
+++ b/os/src/task/id.rs
@@ -87,6 +87,7 @@ impl Drop for KernelStack {
         KERNEL_SPACE
             .exclusive_access()
             .remove_area_with_start_vpn(kernel_stack_bottom_va.into());
+        KSTACK_ALLOCATOR.exclusive_access().dealloc(self.0);
     }
 }
 
diff --git a/user/Cargo.toml b/user/Cargo.toml
index d1816c64..1d7b2efc 100644
--- a/user/Cargo.toml
+++ b/user/Cargo.toml
@@ -16,4 +16,4 @@ oorandom ="11"
 virtio-input-decoder = "0.1.4"
 
 [profile.release]
-debug = true
\ No newline at end of file
+debug = true