Linux driver engineering interview must ask knowledge points

One: Introduction

At first glance, I realized I was looking for a job. My main goal is to work on driver development. Of course, the path to mastering Linux is still long and challenging. I recently had interviews with four companies related to driver development. Only one company, Shenzhen Zhongwei Technology Co., Ltd., left a strong impression on me (or through a phone interview). The questions asked by the engineer weren’t too difficult, but I found it hard to answer them comprehensively. That’s why I decided to write this down—to make sure I fully understand these topics, so I won’t be caught off guard next time.

The other three interviews didn’t even ask about drivers. I’m not sure what they were looking for. Asking technical questions should reflect a candidate’s depth of knowledge. It’s true that driver development can be tough, but I’m determined to keep pushing forward!

Two: Common Linux Kernel Interview Questions (From Easy to Hard)

Basic Level:

1. What is the difference between kernel space and user space in Linux? How do they communicate?

2. How does Linux manage memory? What are virtual addresses and physical addresses? What is high memory?

3. How does Linux handle interrupts? What’s the difference between tasklet and workqueue? Why are there upper and lower halves?

4. What is the process of handling an interrupt in Linux? When is an interrupt handler executed?

5. What synchronization mechanisms exist in Linux? What’s the difference between spinlock and semaphore?

6. How does RCU (Read-Copy-Update) work in Linux?

7. What is the principle behind soft interrupts in Linux? (March 11, 2014)

8. What atomic operations does Linux support? (March 22, 2014)

9. How is the address space divided in a MIPS CPU? How do you access a specific device register in U-Boot? (March 22, 2014)

I’ve been busy lately (due to my resignation), otherwise I would have written more. But I still believe these topics are essential for real-world development. Understanding theory helps you make better decisions when writing code—knowing what to use and what to avoid.

Advanced Level:

1. How does Linux implement netfilter? How are packets processed (e.g., filtering, NAT)? What are the HOOK points?

2. How does a system call work in Linux? For example, how does read() function move from user space to kernel space?

3. What is the Linux kernel startup process at the source code level?

4. What is the scheduling mechanism in Linux?

5. What’s your understanding of the Linux network subsystem?

Three: Written Test Questions

1. Binary search implementation

2. Size conversion and comparison

3. Sum of the outermost elements in a 2D array

4. Check specific bit positions (0 or 1)

5. Swap the first and last characters in a string (string reversal)

If you've encountered any other topics during interviews, feel free to leave a comment. I'll collect them all and prepare a comprehensive list for future interviews.

Under the time constraints, I've compiled these questions and studied them on my own. I hope others can benefit from this and no longer struggle to find resources everywhere.