LPIC-2 Linux Kernel and System Startup — Timed 10 Questions

Question 1

A system administrator needs to ensure that a custom kernel module loads automatically at boot. The module is named 'my_driver' and is built for the current kernel. Which configuration file should be modified to ensure the module loads automatically?

Accepted Answer

Add a configuration file in /etc/modules-load.d/. Option C is correct because systemd-based Linux distributions use /etc/modules-load.d/ to specify kernel modules that should be loaded automatically at boot. Placing a configuration file (e.g., my_driver.conf) containing the module name 'my_driver' in this directory instructs systemd-modules-load.service to load the module during early boot. This is the modern, distribution-agnostic method for ensuring a custom kernel module loads automatically.

Answer

Add the insmod command in /etc/rc.local

Answer

Add the module name to /etc/modules.conf

Answer

Add a configuration file in /etc/modprobe.d/

Question 2

During boot, the kernel outputs a message indicating that a required device driver is not found. Which command can be used to rebuild the initramfs to include the missing driver?

Accepted Answer

dracut. Dracut is the standard tool for building initramfs images on modern Red Hat-based distributions (RHEL, CentOS, Fedora). When a required kernel driver is missing during boot, you can use `dracut --force` to rebuild the initramfs, which will automatically include the currently loaded kernel modules and any specified in configuration files. This ensures the missing driver is available early in the boot process.

Answer

mkinitrd

Answer

grub-mkconfig

Answer

mkinitcpio

Question 3

A server with a custom kernel fails to boot after a kernel update. The system displays a kernel panic: 'VFS: Unable to mount root fs on unknown-block(0,0)'. The root filesystem is on an LVM volume. What is the most likely cause?

Accepted Answer

The initramfs is missing LVM support.. The kernel panic 'VFS: Unable to mount root fs on unknown-block(0,0)' indicates the kernel cannot locate the root filesystem. Since the root filesystem resides on an LVM volume, the initramfs must contain LVM tools and modules to activate the volume group and logical volumes before the kernel can mount the root. If the initramfs was not rebuilt after the kernel update, it will lack LVM support, causing the boot failure.

Answer

The GRUB configuration is pointing to the wrong kernel partition.

Answer

The kernel does not have the necessary device drivers compiled in.

Answer

The root filesystem is formatted with an unsupported filesystem.

Question 4

A system administrator wants to change the default kernel boot parameters temporarily to debug a boot issue. Which step should be taken at the GRUB menu to modify kernel parameters for the next boot only?

Accepted Answer

Select the kernel entry and press 'e' to edit the boot parameters.. Option A is correct because pressing 'e' at the GRUB menu allows you to edit the boot parameters for the selected kernel entry temporarily. This modifies the kernel command line only for the current boot, without persisting changes to disk. After editing, pressing Ctrl+X or F10 boots the system with the modified parameters, making it ideal for debugging boot issues.

Answer

Edit /etc/default/grub and run update-grub to apply changes.

Answer

Press 'c' to enter the command line and modify parameters.

Answer

Press 'Esc' to access the advanced options menu.

Question 5

After installing a new kernel, the system administrator notices that the system boots to the old kernel by default. Which command should be used to update the GRUB configuration to boot the new kernel?

Accepted Answer

update-grub. The `update-grub` command (which is a wrapper for `grub-mkconfig -o /boot/grub/grub.cfg`) scans the installed kernels and regenerates the GRUB configuration file, automatically setting the newest kernel as the default boot entry. This ensures the system boots the newly installed kernel on the next reboot.

Answer

grub-install

Answer

mkinitrd

Answer

grub-set-default

Question 6

A developer has compiled a custom kernel with a new feature. The kernel modules are installed in /lib/modules/$(uname -r)/. However, when the system boots, the kernel fails to load some modules with 'Exec format error'. What is the most likely cause?

Accepted Answer

The modules were compiled against a different kernel version.. The 'Exec format error' indicates that the kernel module binary is incompatible with the running kernel. This most commonly occurs when modules are compiled against a different kernel version (e.g., different kernel source tree or configuration), as the module's vermagic string must exactly match the kernel's vermagic. The kernel's module loader checks this version magic before loading; a mismatch causes the exec format error.

Answer

The kernel configuration has disabled module loading.

Answer

The modules have incorrect file permissions.

Answer

The modules are not properly ordered in the dependency file.

Question 7

A system administrator needs to find out which kernel parameters were passed at boot time. Which command displays the kernel boot parameters?

Accepted Answer

cat /proc/cmdline. The correct command is `cat /proc/cmdline` because the Linux kernel stores the boot parameters (also known as the kernel command line) passed by the bootloader (e.g., GRUB) in the virtual file `/proc/cmdline`. Reading this file directly displays the exact parameters used during boot, such as `root=`, `quiet`, or `splash`.

Answer

dmesg

Answer

lsmod

Answer

cat /proc/version

Question 8

Which TWO of the following commands are used to manage kernel modules? (Select TWO.)

Accepted Answer

insmod. B (insmod) is correct because it directly inserts a kernel module into the running kernel, though it does not resolve dependencies automatically. C (modprobe) is correct because it is the recommended tool for managing kernel modules, as it automatically loads dependencies and handles module parameters via configuration files in /etc/modprobe.d/.

Answer

lsmod

Answer

rmmod

Answer

depmod

Question 9

Which THREE factors can cause a kernel panic during boot? (Select THREE.)

Accepted Answer

Corrupted kernel image. A corrupted kernel image (Option B) is a direct cause of kernel panic during boot because the bootloader (e.g., GRUB) loads the kernel into memory, and if the binary is damaged (e.g., due to disk errors or incomplete update), the CPU will attempt to execute invalid instructions, triggering a fatal kernel panic. The kernel performs integrity checks early in startup, and any mismatch between expected and actual code will halt the system with a panic message.

Answer

Too many kernel modules loaded

Answer

Filesystem errors on the root partition

Question 10

A company runs a critical web server on a custom-built Linux distribution. The server has been stable for months, but after a recent kernel update from version 5.10 to 5.15, the server experiences intermittent crashes. The crashes occur under heavy load and are accompanied by kernel oops messages mentioning a NULL pointer dereference in a network driver. The network driver is a third-party module that was compiled against the old kernel. The system administrator has recompiled the module against the new kernel, but the crashes persist. The server has 64 GB of RAM and uses a bonded network interface with two 10 GbE NICs. The kernel oops trace points to a function in the bonding driver. Which of the following is the most likely cause of the crashes?

Accepted Answer

Check the kernel configuration changes between versions 5.10 and 5.15 that affect the bonding driver.. Option C is correct because the crashes persist after recompiling the third-party network driver, and the oops trace points to the bonding driver. This indicates that the issue is likely due to changes in the kernel's internal APIs or data structures between versions 5.10 and 5.15 that affect the bonding driver, not the third-party module. The bonding driver is part of the kernel itself, so it must be compatible with the new kernel version; checking kernel configuration changes (e.g., modifications to `struct net_device`, bonding sysfs interfaces, or locking mechanisms) is the appropriate next step.

Answer

Increase the system memory to reduce memory pressure.

Answer

Update the firmware on the network interface cards.

Answer

Recompile the network driver module with debugging enabled.