通过qemu调试centos7内核

Posted 2022-02-07 rayylee

1.安装依赖

sed -e 's|^mirrorlist=|#mirrorlist=|g' \\
        -e 's|^#baseurl=http://mirror.centos.org|baseurl=https://mirrors.tuna.tsinghua.edu.cn|g' \\
        -i.bak \\
        /etc/yum.repos.d/CentOS-*.repo
yum install -y vim wget lrzsz
yum install -y gcc bc gcc-c++ ncurses ncurses-devel cmake elfutils-libelf-devel openssl-devel libgcrypt-devel glibc-static
yum install -y qemu-kvm gdb net-tools texinfo

systemctl stop firewalld
systemctl mask firewalld
setenforce 0
sed ‐i '/^SELINUX/s/=.*/=disabled/' /etc/selinux/config

2.下载内核版本解压并进入解压目录

wget https://vault.centos.org/7.9.2009/os/Source/SPackages/kernel-3.10.0-1160.el7.src.rpm

3.清理内核源目录

make mrproper

4.使用make menuconfig菜单来订制内核功能

make menuconfig
(
  配置ext4、virtio为 Y
  修改Makefile: -O2改为-O1; 删掉-Werror 
)

5.编译内核

make vmlinux -j 4
make bzImage

6. 通过qemu-kvm调试内核

/usr/libexec/qemu-kvm -kernel arch/x86/boot/bzImage -initrd initramfs.cpio.gz -s -S -append nokaslr -vnc :0

-kernel bzImage：指定内核路径
-initrd file:指定initramdisk路径
-s:-gdb tcp::1234的缩写, 开启一个gdbserver, 可以通过TCP端口1234连接
-S: 启动后立即暂停
-append nokaslr: 指定内核参数nokaslr, 禁止内核地址随机化, 否则gdb打断点找不到地址
-vnc :0: 开启vnc监听0端口

打开另一个终端

gdb vmlinux 
或者
gdb vmlinux --tui

(gdb) target remote:1234
Remote debugging using :1234
0x0000000000000000 in irq_stack_union ()
(gdb) hb start_kernel      // 设置硬件断点
Hardware assisted breakpoint 1 at 0xffffffff81d9ae44: file init/main.c, line 489.
(gdb) info b
Num     Type           Disp Enb Address            What
1       hw breakpoint  keep y   0xffffffff81d9ae44 in start_kernel at init/main.c:489
  breakpoint already hit 1 time
(gdb) c
Continuing.

Breakpoint 1, start_kernel () at init/main.c:489
489