我已经在 Ubuntu 20.04 上安装了 xanmod 内核（5.13），但它没有出现在 grub 菜单中。
$ ls -la /boot
total 374776
drwxr-xr-x 5 root root 4096 Sep 11 11:44 .
drwxr-xr-x 20 root root 4096 Aug 11 2020 ..
-rw-r--r-- 1 root root 251162 Apr 16 11:35 config-5.11.15-051115-generic
-rw-r--r-- 1 root root 256848 Sep 8 15:52 config-5.13.15-xanmod1
-rw-r--r-- 1 root root 237769 Sep 10 2020 config-5.4.0-48-generic
drwx------ 3 root root 4096 Jan 1 1970 efi
drwxr-xr-x 5 root root 4096 Sep 11 12:17 grub
lrwxrwxrwx 1 root root 33 Sep 5 14:47 initrd.img -> initrd.img-5.11.15-051115-generic
-rw-r--r-- 1 root root 95484965 Sep 11 11:41 initrd.img-5.11.15-051115-generic
-rw-r--r-- 1 root root 154095831 Sep 11 11:42 initrd.img-5.13.15-xanmod1
-rw-r--r-- 1 root root 82174073 Sep 11 11:41 initrd.img-5.4.0-48-generic
lrwxrwxrwx 1 root root 27 Sep 5 14:47 initrd.img.old -> initrd.img-5.4.0-48-generic
drwx------ 2 root root 16384 Aug 11 2020 lost+found
-rw-r--r-- 1 root root 182704 Aug 18 2020 memtest86+.bin
-rw-r--r-- 1 root root 184380 Aug 18 2020 memtest86+.elf
-rw-r--r-- 1 root root 184884 Aug 18 2020 memtest86+_multiboot.bin
-rw------- 1 root root 5954147 Apr 16 11:35 System.map-5.11.15-051115-generic
-rw-r--r-- 1 root root 4762070 Sep 8 15:52 System.map-5.13.15-xanmod1
-rw------- 1 root root 4743112 Sep 10 2020 System.map-5.4.0-48-generic
lrwxrwxrwx 1 root root 30 Sep 5 14:47 vmlinuz -> vmlinuz-5.11.15-051115-generic
-rw------- 1 root root 14336896 Apr 16 11:35 vmlinuz-5.11.15-051115-generic
-rw-r--r-- 1 root root 9162976 Sep 8 15:52 vmlinuz-5.13.15-xanmod1
-rw------- 1 root root 11678464 Sep 10 2020 vmlinuz-5.4.0-48-generic
lrwxrwxrwx 1 root root 24 Sep 5 14:47 vmlinuz.old -> vmlinuz-5.4.0-48-generic
$ sudo update-grub2
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.11.15-051115-generic
Found initrd image: /boot/initrd.img-5.11.15-051115-generic
Found linux image: /boot/vmlinuz-5.11.15-051115-generic
Found initrd image: /boot/initrd.img-5.11.15-051115-generic
Found linux image: /boot/vmlinuz-5.4.0-48-generic
Found initrd image: /boot/initrd.img-5.4.0-48-generic
Found memtest86+ image: /memtest86+.elf
Found memtest86+ image: /memtest86+.bin
done
看起来update-grub2(也update-grub) 两次检测内核 5.11，而根本没有检测 xanmod 内核 5.13？为什么会这样？
答案1
如果你安装了 debian lowlatency 内核，那么文件 /etc/grub.d/09_lowlatency 会阻止 update-grub 看到 xanmod 内核
方法 1 删除低延迟内核：
sudo apt remove linux-image-lowlatency
方法2 在/etc/grub.d中创建一个新模块：
sudo cp /etc/grub.d/09_lowlatency /etc/grub.d/08_xanmod
sudo vi /etc/grub.d/08_xanmod
在 /etc/grub.d/08_xanmod 中添加以下内容
--- /etc/grub.d/09_lowlatency 2021-06-25 19:34:13.000000000 -0700
+++ /etc/grub.d/08_xanmod 2022-01-16 06:56:27.014767317 -0800
@@ -36,6 +36,11 @@
export TEXTDOMAIN=grub
export TEXTDOMAINDIR="${datarootdir}/locale"
+# only 08_xanmod or 09_lowlatency should run, since we got this far
+# 09_lowlatency should not run next
+if [ -x /etc/grub.d/09_lowlatency ]; then
+ chmod -x /etc/grub.d/09_lowlatency
+fi
# only 09_lowlatency or 10_linux should run, since we got this far
# 10_linux should not run next
if [ -x /etc/grub.d/10_linux ]; then
@@ -247,6 +252,9 @@
case "x$machine" in
xi?86 | xx86_64)
list=
+ for i in /boot/vmlinuz-*xanmod1; do
+ if grub_file_is_not_garbage "$i" ; then list="$list $i" ; fi
+ done
for i in /boot/vmlinuz-*lowlatency /vmlinuz-*lowlatency /boot/kernel-*lowlatency ; do
if grub_file_is_not_garbage "$i" ; then list="$list $i" ; fi
done
最后使用新模块更新 grub conf
sudo update-grub2