diff --git a/.gitignore b/.gitignore
index 7fb857d0..676c060d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,6 +5,7 @@ os/src/link_app.S
 os/src/linker.ld
 os/last-*
 os/Cargo.lock
+os/.gdb_history
 user/target/*
 user/.idea/*
 user/Cargo.lock
diff --git a/easy-fs/Cargo.toml b/easy-fs/Cargo.toml
index 6e7cd925..c9690776 100644
--- a/easy-fs/Cargo.toml
+++ b/easy-fs/Cargo.toml
@@ -8,4 +8,7 @@ edition = "2018"
 
 [dependencies]
 spin = "0.7.0"
-lazy_static = { version = "1.4.0", features = ["spin_no_std"] }
\ No newline at end of file
+lazy_static = { version = "1.4.0", features = ["spin_no_std"] }
+
+[profile.release]
+debug = true
diff --git a/os/Cargo.toml b/os/Cargo.toml
index b07fa034..8b81163b 100644
--- a/os/Cargo.toml
+++ b/os/Cargo.toml
@@ -20,4 +20,7 @@ easy-fs = { path = "../easy-fs" }
 
 [features]
 board_qemu = []
-board_k210 = []
\ No newline at end of file
+board_k210 = []
+
+[profile.release]
+debug = true
diff --git a/os/Makefile b/os/Makefile
index 0c1fb7c7..91ae60bf 100644
--- a/os/Makefile
+++ b/os/Makefile
@@ -14,6 +14,11 @@ SBI ?= rustsbi
 BOOTLOADER := ../bootloader/$(SBI)-$(BOARD).bin
 K210_BOOTLOADER_SIZE := 131072
 
+# Building mode argument
+ifeq ($(MODE), release)
+	MODE_ARG := --release
+endif
+
 # KERNEL ENTRY
 ifeq ($(BOARD), qemu)
 	KERNEL_ENTRY_PA := 0x80200000
@@ -106,4 +111,11 @@ debug: build
 		tmux split-window -h "riscv64-unknown-elf-gdb -ex 'file $(KERNEL_ELF)' -ex 'set arch riscv:rv64' -ex 'target remote localhost:1234'" && \
 		tmux -2 attach-session -d
 
-.PHONY: build env kernel clean disasm disasm-vim run-inner switch-check fs-img
+
+gdbserver: build
+	@qemu-system-riscv64 -machine virt -nographic -bios $(BOOTLOADER) -device loader,file=$(KERNEL_BIN),addr=$(KERNEL_ENTRY_PA) -s -S
+
+gdbclient:
+	@riscv64-unknown-elf-gdb -ex 'file $(KERNEL_ELF)' -ex 'set arch riscv:rv64' -ex 'target remote localhost:1234'
+
+.PHONY: build env kernel clean disasm disasm-vim run-inner switch-check fs-img gdbserver gdbclient
diff --git a/rust-toolchain b/rust-toolchain
index 925656db..abcacd9b 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2022-01-19
+nightly-2022-04-11
diff --git a/user/Cargo.toml b/user/Cargo.toml
index f522c9e9..542a624a 100644
--- a/user/Cargo.toml
+++ b/user/Cargo.toml
@@ -10,3 +10,6 @@ edition = "2018"
 buddy_system_allocator = "0.6"
 bitflags = "1.2.1"
 riscv = { git = "https://github.com/rcore-os/riscv", features = ["inline-asm"] }
+
+[profile.release]
+debug = true
diff --git a/user/src/bin/early_exit.rs b/user/src/bin/early_exit.rs
new file mode 100644
index 00000000..bf69e242
--- /dev/null
+++ b/user/src/bin/early_exit.rs
@@ -0,0 +1,22 @@
+#![no_std]
+#![no_main]
+
+#[macro_use]
+extern crate user_lib;
+extern crate alloc;
+
+use user_lib::{thread_create, exit};
+use alloc::vec::Vec;
+
+pub fn thread_a() -> ! {
+    for i in 0..1000 { print!("{}", i); }
+    exit(1)
+}
+
+#[no_mangle]
+pub fn main() -> i32 {
+    thread_create(thread_a as usize, 0);
+    println!("main thread exited.");
+    exit(0)
+}
+