Master LDD Interview Questions (2026)

On: January 10, 2026

LDD interview questions with clear answers for freshers and experienced engineers. Covers character drivers, platform drivers, device tree, and kernel basics.

Preparing for a Linux Device Driver interview can feel overwhelming, especially when questions go deep into kernel internals, memory management, and hardware interaction. This curated collection of Linux Device Driver (LDD) Interview Questions is designed to help both freshers and experienced embedded/Linux engineers confidently crack technical interviews.

In this guide, you’ll find real interview questions asked in Round 1 and Round 2, covering both theoretical concepts and practical kernel programming scenarios. The questions focus on character drivers, platform drivers, device tree, kernel modules, interrupt handling, memory mapping, synchronization, and system call flow, which are commonly discussed by interviewers in embedded and Linux kernel roles.

Whether you’re targeting roles like Linux Device Driver Developer, Embedded Linux Engineer, Kernel Developer, or Automotive Software Engineer, these questions will strengthen your fundamentals and improve your problem-solving approach.

This resource is especially useful if you are preparing for interviews at product-based companies, automotive firms, startups, or MNCs, where deep knowledge of Linux internals is expected. By practicing these LDD interview questions, you’ll gain clarity on how drivers interact with hardware, how the Linux kernel manages resources, and how to debug real-world driver issues.

If you are serious about building a career in Embedded Systems and Linux Kernel Development, this Linux Device Driver interview question set is a must-read.

1. Basics of Linux Device Drivers

What is a device driver in Linux?
Why are device drivers required?
What are the main types of device drivers in Linux?
What is the difference between a device driver and an application?
What is a kernel module?
What is the difference between built-in drivers and loadable kernel modules?
How do you load and unload a kernel module?
What are insmod, rmmod, modprobe, and lsmod?
What is dmesg and why is it used?
What is /proc and /sys filesystem?

2. Device Driver Types

What is a character device driver?
What is a block device driver?
What is a network device driver?
Give examples of character and block devices.
When should you use a character driver vs a platform driver?
Can a platform driver be a character driver?

3. Character Device Driver

What is a major and minor number?
How does the kernel identify a device file?
What is register_chrdev()?
What is alloc_chrdev_region()?
What is struct file_operations?
Explain open(), read(), write(), and release() in drivers.
What is copy_to_user() and copy_from_user()?
Why can’t we directly access user space memory from kernel space?
What is udev?

4. Platform Devices and Drivers

What is a platform device?
What is a platform driver?
Why are platform drivers used?
What is device tree?
Why is device tree required?
What is a compatible string?
How does the kernel match a platform device with a platform driver?
What is probe() and remove()?
Where is hardware information stored in device tree?
Is device tree mandatory for platform drivers?

5. Kernel Space vs User Space

What is kernel space?
What is user space?
Why is kernel space protected?
Can kernel directly access user memory?
What happens during a system call?

6. Memory Management in Drivers

What is kmalloc()?
Difference between kmalloc() and vmalloc()?
What is GFP_KERNEL?
What is memory leak in kernel?
How do you debug memory leaks in drivers?
What is DMA?
What is coherent vs non-coherent DMA?

7. Interrupts

What is an interrupt?
What is ISR (Interrupt Service Routine)?
What is top half and bottom half?
What are softirqs?
What are tasklets?
What are workqueues?
Why should ISR be short?
How do you register an interrupt handler?

8. Concurrency and Synchronization

What is a race condition?
What is a spinlock?
Difference between mutex and spinlock?
When do you use mutex vs spinlock?
What is atomic operation?
What is semaphore?
What is deadlock?

9. Device Driver Debugging

How do you debug a kernel driver?
What is printk()?
What are printk log levels?
What is ftrace?
What is kgdb?
How do you handle kernel panic?

10. Device Tree (DTS)

What is DTS and DTB?
How is DTS compiled?
What is a node and property?
What is reg property?
What is interrupts property?
How do drivers read device tree data?
What is of_match_table?

11. Advanced Driver Concepts

What is a bus in Linux?
Difference between platform bus, I2C bus, SPI bus?
What is a resource manager?
What is power management in drivers?
What is suspend and resume?
What is runtime power management?
What is hot-plugging?
What is sysfs interface?
How do you expose driver data to user space?

12. Linux Driver Build & Deployment

How do you write a Makefile for kernel modules?
What is Kconfig?
Difference between monolithic kernel and modular kernel?
How do you cross-compile a driver?
How do you insert a driver at boot time?
What is initramfs?

13. Interview Scenario-Based Questions

How would you write a driver for an LED?
How does the kernel know which hardware is connected?
How would you handle multiple devices using one driver?
What happens if probe fails?
How do you ensure driver portability?
How do you write a driver without device tree?
How do you test a driver?
What precautions are required while writing kernel code?
What happens if a driver crashes?
Why is kernel programming considered risky?

Bonus: Common Follow-Up Questions

Explain driver flow from boot to device access
Explain system call flow for read()
Explain character driver vs platform driver with real example
Explain how user application communicates with driver

Conclusion

Linux Device Driver interview preparation is not just about answering questions, but about understanding how the Linux kernel interacts with hardware. By practicing these LDD interview questions, you build strong core concepts, improve your debugging skills, and gain the confidence needed to face real technical interviews. With consistent learning and hands-on practice, you can crack Linux Device Driver interviews and grow as a skilled Embedded or Kernel Developer.

Frequently Asked Questions (FAQ) : Linux Device Driver Interview Questions

1. What are Linux Device Driver interview questions?

Linux Device Driver interview questions focus on how the Linux kernel communicates with hardware. These questions usually cover topics like character drivers, platform drivers, device trees, interrupts, memory management, system calls, and kernel modules. They test both conceptual understanding and practical coding skills.

2. Are Linux Device Driver interview questions hard for beginners?

They can feel challenging at first, but beginners can crack them by starting with basics such as driver types, kernel space vs user space, and file operations (open, read, write). With regular practice and hands-on driver development, these questions become much easier to understand.

3. What topics are most important for LDD interviews?

The most important topics include character drivers, platform drivers, device tree, kernel module lifecycle, interrupt handling, memory mapping (ioremap), synchronization mechanisms, and system call flow. Interviewers often expect strong fundamentals in these areas.

4. What is the difference between Round 1 and Round 2 LDD interview questions?

Round 1 usually focuses on basic concepts, theory, and simple code understanding. Round 2 is more in-depth and practical, covering real-world scenarios like driver debugging, hardware interaction, race conditions, and performance issues in the kernel.

5. Do Linux Device Driver interviews require coding?

Yes, most interviews include coding-related questions. You may be asked to write a simple character driver, explain kernel APIs, or debug a driver issue. Even if live coding is not required, you should clearly explain how you would implement a driver.

6. Is device tree knowledge mandatory for Linux Device Driver interviews?

Yes, device tree knowledge is very important, especially for embedded Linux roles. Interviewers often ask how the kernel identifies hardware, how drivers match with device tree nodes, and how platform drivers use device tree data.

7. How can I prepare for Linux Device Driver interviews effectively?

The best way to prepare is by combining theory with hands-on practice. Write small drivers, understand kernel logs using dmesg, explore /proc and /sys, and practice explaining concepts in simple terms. Revising common LDD interview questions regularly also helps a lot.

8. Are these LDD interview questions useful for experienced engineers?

Absolutely. Experienced engineers are often tested on deeper kernel internals, optimization, synchronization, and debugging. These Linux Device Driver interview questions help refresh fundamentals and prepare for advanced discussion rounds.

9. Which job roles ask Linux Device Driver interview questions?

Roles like Linux Device Driver Developer, Embedded Linux Engineer, Kernel Developer, BSP Engineer, and Automotive Software Engineer commonly ask LDD interview questions during technical interviews.

10. Can learning LDD interview questions help in real projects?

Yes. These questions are closely related to real-world driver development. Understanding them improves your ability to write stable drivers, debug kernel issues, and work efficiently with hardware in production systems.