Learning eBPF the Hard Way: What the Linux Kernel Doesn’t Tell You

My first real experience with eBPF taught me that kernel programming is less about logic and more about constraints and verification rules.

Problem

Traditional monitoring tools don’t provide deep kernel visibility, but writing eBPF programs is difficult due to strict verifier rules and limited debugging feedback.

• eBPF verifier rejects programs without clear explanations.
• Hard to understand kernel-level execution flow.
• Limited debugging tools for failed programs.
• Strict constraints on memory and loops in eBPF.

Solution

👉 Using eBPF for SSH monitoring and kernel observability experiments

• Used tracepoints and uprobes for SSH monitoring
• Captured authentication and connection events in real time
• Built structured logging for system activity
• Experimented with safer ways to design eBPF programs
• Focused on understanding kernel observability patterns

Architecture Diagram

Rendered using Mermaid for scalable diagram authoring.

flowchart TD
A[User Space] --> B[eBPF Program]
B --> C[Kernel Verifier]
C --> D[Kernel Hooks]
D --> E[System Events]
E --> F[SSH / Auth Logs]
E --> G[Network / Syscalls]