r/kernel

CISA has added CVE-2026-43456, a Linux kernel local privilege escalation vulnerability, to its Known Exploited Vulnerabilities (KEV) catalog following confirmed in-the-wild exploitation. Here's everything covering the affected kernel versions, the vulnerability itself, which distributions have shipped fixes, and the available mitigations. If you're maintaining Linux systems, it may be worth checking whether your kernel has already been updated by your distro. Patch Now.

Hi everyone,

I recently made it to the final loop for a specialized systems role at a major silicon company . The technical panel round went incredibly well, but in the final "coding bar" round, I was hit with a textbook Dynamic Programming (DP) question. I solved it through recursion and explained space and time complexity too. It was In-person white boarding coding round.But the optimized solution done using DP. So, I was ultimately rejected for "lacking strong programming skills."

Frankly, it’s frustrating. In my daily world, allocating massive, multi-dimensional DP arrays inside the kernel is a great way to cause memory exhaustion, latency spikes, or a straight-up kernel panic. We care about deterministic execution, restricted stack space, ring buffers, and bit manipulation ,not finding the edit distance of two strings.

Since I am preparing for other top-tier systems/silicon companies (Apple, NVIDIA, Amazon Robotics, Dell), I want to make sure I am prepared for the inevitable generic "coding puzzle" interviewer who doesn't know what a device driver is.

For those of you working in kernel space or hiring for low-level systems, what data structures and algorithmic patterns do you actually consider mandatory to see from a candidate?

My current checklist to review is:

• Bit Manipulation (masks, bitwise operations, clearing/setting registers)
• Concurrency & Synchronization (handling race conditions, producer-consumer with circular/ring buffers)
• Linked Lists & Trees (kernel-style list_head manipulation, basic tree traversal)
• Pointer Arithmetic & Memory Management (custom allocators, page-alignment calculations, string/buffer parsing without helper libraries)
• General patterns like two-pointer, sliding window, Prefix Sum,recursion and sorting.

Should I suck it up and grind standard LeetCode DP/Graph patterns just to pass the cross-functional corporate interviewers, or are there specific systems-adjacent coding patterns I should focus on maximizing?

Would love to hear your thoughts or similar interview horror stories. Thanks!

Hi everyone,

I work as a Linux kernel developer at a large semicon. I have ~2 years of total exp with about 1 year in kernel development.

I'm working on a fairly large legacy driver where multiple years of fixes, features and hardware support have accumulated. Reading the code is often overwhelming because understanding one path requires tracing through device tree parsing, probe, private data initialization, IRQs, workqueues, callbacks, multiple execution contexts, etc.

I can usually understand individual pieces after spending enough time but I struggle to build and retain a complete mental model of the subsystem. During discussions with senior engineers, I keep forgetting the exact execution flow or where a particular structure (for ex, driver private data populated from DT/SoC information, IRQ calls that come from GIC and the flow afterwards) was initialized, even though I understood it while debugging.

Another issue I've identified is that when deadlines are tight, I tend to rely on LLMs to quickly understand the relevant code path so I can fix a bug or implement a feature. While this helps in the short term, I feel it's hurting my ability to deeply understand the codebase, so I'm trying to reduce that habit.

I'm curious:

- Is this a normal stage for someone with ~1 year of kernel experience?

- How do experienced kernel developers approach understanding large legacy drivers?

- Also how to develop patience to read the code for hours together ? I do love it when I understand a function or a call flow but I feel like the speed isn't enough and my patience to understand something in depth drops after digging in for sometime

I'd really appreciate any advice or habits that helped you early in your kernel career.

https://preview.redd.it/zlr37c1qt7ah1.png?width=320&format=png&auto=webp&s=e84dffd8519b790a01f2d431c47387d848598d23

Hello everyone, I created a simple firewall used by netfilter hooks and netlink sockets to communicate between the kernel and the user space. Please, can anyone check it and give me feedback on this project, and which part I can write better or which part write mistake. Repo

Hi everyone!

I have become very passionate about OS development recently, and I've been wondering what steps I should take to land an OS dev role. I recently graduated, so I am fairly early in my career path and currently exploring my options. I wrote an OS from scratch for my bachelor's engineering thesis, which I think was a good start.

I would appreciate any advice or ideas!