VirtualBox: How to compile Linux Kernel on a Debian Guest

Debian Packages

See https://doit.vlsm.org/026.html#idx02 for more details.

Download Latest STABLE Kernel

Fetch the latest STABLE kernel from https://kernel.org/.

# START =============================================================

# VARIABLES
STABLE=$(wget -O - -o /dev/null https://www.kernel.org/finger_banner | awk '/stable/ {print $NF; exit}')
MAJOR=$(echo $STABLE | cut -d. -f1)
URL="https://kernel.org/pub/linux/kernel/v$MAJOR.x"
KERNEL="linux-$STABLE.tar.xz"
TARBALL="linux-$STABLE.tar"
PGP="linux-$STABLE.tar.sign"
KURL="$URL/$KERNEL"
PURL="$URL/$PGP"

# ===================================================================
# Download the latest stable kernel tarball
wget -c $KURL

# ===================================================================
# Download  the signature
wget -c $PURL

# ===================================================================
# Locate and import the PGP keys for verification
gpg --locate-keys torvalds@kernel.org gregkh@kernel.org

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Sign Key (optional)

gpg --sign-key gregkh@kernel.org

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Uncompress the file and verify

# ===================================================================
# Uncompress the kernel tarball
unxz $KERNEL

# Verify the tarball signature
gpg --verify $PGP $TARBALL

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Extract TAR file

# ===================================================================
# Extract the kernel tarball
tar xvf $TARBALL

# ===================================================================
# Enter the kernel source directory
cd linux-$STABLE

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Overkilled Cleaning Habit

Once in a while, someone will ask about why not “make distclean,” or “make mrproper,” or “make clean.” Ok, this is the way! ℼ

make distclean; make mrproper; make clean;

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AMD64 Option 1: Reusing “.config” files

If copying a wrong “.config” file, you might create a massive kernel with huge modules.
- Consider copying a working “.config” file from the “/boot/” directory.
- Or, try to download this “.config” file
  - See also Linux/AMD64 Kernel Config for VirtualBox.
- Or, try to reuse any .config file. ℼ
Run:

yes "" | make oldconfig

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AMD64 OPTION 2: A “.config” file from scratch

If OPTION 1 failed, consider making a “.config” file from scratch with:

make x86_64_defconfig
yes "" | make oldconfig

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Menuconfig

make menuconfig

E.g., for cbkadal

General setup  --->
  (-cbkadal-10) Local version - append to kernel release
  Kernel compression mode (XZ)  --->
  (cbkadal) Default hostname
  <*> Kernel .config support
  [*] Enable access to .config through /proc/config.gz
  <*> Enable kernel headers through /sys/kernel/kheaders.tar.xz
Processor type and features  --->
  [ ] EFI runtime service support 
[*] Enable loadable module support  --->
  [*]   Module unloading
  [*]     Forced module unloading
  [*]   Module versioning support
File systems  --->
  <*> FUSE (Filesystem in Userspace) support
  <*>   Character device in Userspace support
  <*>   Virtio Filesystem 
Security options  --->
  [ ] NSA SELinux Support
  [*] AppArmor support
  [*]   Enable introspection of sha1 hashes for loaded profiles
  [*]     Enable policy hash introspection by default
  First legacy 'major LSM' to be initialized
    (X) AppArmor
Kernel hacking  --->  
  printk and dmesg option --->
    [*] Enable dynamic printk() support
  Compile-time checks and compiler options  --->
    [*] Install uapi headers to usr/include

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Compile (make)

time make

FYI Compile Time: ℼ
- (Linux) Intel(R) Core(TM) i5-9400F CPU @ 2.90GHz
  - real 3m5.825s
  - user 14m51.339s
  - sys 1m59.721s
- (Windows 10) Intel(R) Core(TM) i5-9400F CPU @ 2.90GHz
  - real 4m17.702s
  - user 21m29.718s
  - sys 2m21.400s
- (Linux) Lenovo E135 (AMD E2-2000 APU with Radeon(tm) HD Graphics)
  - real 123m25,746s
  - user 211m58,046s
  - sys 28m1,298s
- (Linux) Lenovo Yoga 300 (Intel(R) Celeron(R) CPU N2840 @2.16GHz)
  - real 69m6,574s
  - user 115m1,006s
  - sys 19m12,436s
- (Windows 10) Lenovo Yoga 300 (Intel(R) Celeron(R) CPU N2840 @2.16GHz)
  - real 4580m11.804s (Yes, there is something wrong here!)
  - user 6900m36.555s
  - sys 864m34.820s
    - One More Time (after fixing the Windows 10 drivers):
      - real 72m26.981s
      - user 114m32.041s
      - sys 24m54.993s

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Install

Use sudo ℼ

# USER: ROOT ============
# Install the modules
sudo make modules_install

# Install the kernel
sudo make install

# Install the headers
sudo make headers_install INSTALL_HDR_PATH=/usr

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Cleaning

You need to keep some parts of the Linux kernel source. You can delete the rest.

make clean
rm -rf arch/[a-u]* arch/xtensa/ block/ certs/ crypto/ Documentation/ 
rm -rf drivers/ fs/ init/ io_uring/ ipc/ kernel/ lib/ lib/ 
rm -rf mm/ net/ rust/ samples/ security/ sound/ virt/ usr/

Linux Firmware

URL: https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/
- E.g. TARBALL “linux-firmware-20220509.tar.gz”
  - open the TARBALL
  - Go to folder “linux-firmware-20220509/”
  - Copy the missing modules into “/lib/firmware/”. E.g. (ROOT),

cp -r i915/ /lib/firmware/
cp -r tigon/ /lib/firmware/
cp -r e100/ /lib/firmware/
cp -r rtl_nic/ /lib/firmware/

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Old Modules

You have to delete old modules (/lib/modules) and old config (/boot/) files manually. Do not forget to “update-grub”.
Visit (ROOT):

cd /lib/modules/
ls -al
cd /boot/
ls -al

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Table of Content

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