记录一下ubuntu内核编译步骤：

sudu su
cd /usr/src/
tar –zxvf  linux-5.2.21.tar.gz
#给内核打上实时性补丁
patch  -p1  <  ../patch-5.4.123-rt59.patch
make mrproper
cp /boot/config-XXX .config
make menuconfig

#General setup->Preemption Model->选择Fully Preemptible Kernel (RT)

#可能需要下载的一些环境配置
sudo apt-get update
sudo apt-get install libncurses5-dev
sudo apt-get install build-essential
sudo apt-get install flex
sudo apt-get install bison
sudo apt-get install openssl
sudo apt-get install libssl-dev

#编译：
make -j8
make modules_install
make install
#我的报Missing file: arch/x86/boot/bzImage
make bzImage
#又报/bin/sh: 1: lz4c: not found
apt-get install liblz4-tool
#再次make bzImage，然后make install 成功了

#内核编译完成后从内核启动时可能会出现 ubuntu error: couldn't find suitable memory target
#解决方法：安装模块的时候加参数INSTALL_MOD_STRIP=1
sudo make INSTALL_MOD_STRIP=1 modules_install