LFD420 Linux Kernel Internals und Development

Seminarinformationen

Seminar - Ziel

In diesem 4-tägigen Seminar „LFD420 Linux Kernel Internals und Development“ erwerben Sie ein tiefgehendes Verständnis für die Entwicklung im Linux-Kernel. Sie lernen die Architektur von Linux kennen, machen sich mit grundlegenden Entwicklungsmethoden im Kernel vertraut und erfahren, wie Sie effizient mit der Linux-Entwickler-Community zusammenarbeiten können.

Das Seminar bietet umfassende Einblicke in Kernel-Algorithmen, Speicher- und Hardwaremanagement sowie in die internen Abläufe des Systems. Sie erlernen Techniken für das Debugging, die Erstellung von Kernel-Modulen und die Integration eigener Entwicklungen. Die vermittelten Inhalte sind praxisnah und auf alle gängigen Linux-Distributionen übertragbar. Dieses Seminar richtet sich an alle, die sich intensiv mit dem Linux-Kernel auseinandersetzen und fundierte Kenntnisse in der Kernel-Entwicklung aufbauen möchten.

Teilnehmer - Zielgruppe

• Entwickler

Kurs - Voraussetzungen

• Gute Kenntnisse der Programmiersprache C
• Grundlegende Kenntnisse von Linux-/UNIX-Dienstprogrammen wie ls, grep und tar
• Sicherer Umgang mit einem Texteditor (z. B. emacs, vi oder vergleichbar)
• Erfahrung mit einer gängigen Linux-Distribution ist hilfreich, aber nicht zwingend erforderlich

Seminardauer

• 4 Tage
• 09:00 Uhr bis 17:00 Uhr

Schulungsunterlagen

• nach Absprache

Seminar-Inhalt / Agenda

Introduction

• Objectives
• Who You Are
• The Linux Foundation{
• Copyright and No Confidential Information
• The Linux Foundation{ Training
• Certification Programs and Digital Badging
• Linux Distributions
• Platforms
• Preparing Your System
• Using and Downloading a Virtual Machine
• Things Change in Linux and Open Source Projects
• Documentation and Links

Preliminaries

• Procedures
• Kernel Versions
• Kernel Sources and Use of git
• Labs

How to Work in OSS Projects

• Overview on How to Contribute Properly
• Know Where the Code is Coming From: DCO and CLA
• Stay Close to Mainline for Security and Quality
• Study and Understand the Project DNA
• Figure Out What Itch You Want to Scratch
• Identify Maintainers and Their Work Flows and Methods
• Get Early Input and Work in the Open
• Contribute Incremental Bits, Not Large Code Dumps
• Leave Your Ego at the Door: Don't Be Thin-Skinned
• Be Patient, Develop Long Term Relationships, Be Helpful

Kernel Architecture I

• UNIX and Linux **
• Monolithic and Micro Kernels
• Object-Oriented Methods
• Main Kernel Components
• User-Space and Kernel-Space

Kernel Programming Preview

• Error Numbers and Getting Kernel Output
• Task Structure
• Memory Allocation
• Transferring Data between User and Kernel Spaces
• Object-Oriented Inheritance - Sort Of
• Linked Lists
• String to Number Conversions
• Jiffies
• Labs

Modules

• What are Modules?
• A Trivial Example
• Compiling Modules
• Modules vs Built-in
• Module Utilities
• Automatic Module Loading
• Module Usage Count
• The module struct
• Module Licensing
• Exporting Symbols
• Resolving Symbols **
• Labs

Kernel Architecture II

• Processes, Threads, and Tasks
• Process Context
• Kernel Preemption
• Real Time Preemption
• Dynamic Kernel Patching
• Run-time Alternatives **
• Porting to a New Platform **
• Labs

Kernel Initialization

• Overview of System Initialization
• System Boot
• Das U-Boot for Embedded Systems**
• Kernel Startup

Kernel Configuration and Compilation

• Installation and Layout of the Kernel Source
• Kernel Browsers
• Kernel Configuration Files
• Kernel Building and Makefiles
• initrd and initramfs
• Labs

System Calls

• What are System Calls?
• Available System Calls
• How System Calls are Implemented
• Adding a New System Call
• Labs

Kernel Style and General Considerations

• Coding Style
• kernel-doc **
• Using Generic Kernel Routines and Methods
• Making a Kernel Patch
• sparse
• Using likely() and unlikely()
• Writing Portable Code, CPU, 32/64-bit, Endianness
• Writing for SMP
• Writing for High Memory Systems
• Power Management
• Keeping Security in Mind
• Mixing User- and Kernel-Space Headers **
• Labs

Race Conditions and Synchronization Methods

• Concurrency and Synchronization Methods
• Atomic Operations
• Bit Operations
• Spinlocks
• Seqlocks
• Disabling Preemption
• Mutexes
• Semaphores
• Completion Functions
• Read-Copy-Update (RCU)
• Reference Counts
• Labs

SMP and Threads

• SMP Kernels and Modules
• Processor Affinity
• CPUSETS
• SMP Algorithms - Scheduling, Locking, etc.
• Per-CPU Variables **
• Labs

Processes

• What are Processes?
• The task_struct
• Creating User Processes and Threads
• Creating Kernel Threads
• Destroying Processes and Threads
• Executing User-Space Processes From Within the Kernel
• Labs

Process Limits and Capabilities **

• Process Limits
• Capabilities
• Labs

Monitoring and Debugging

• Debuginfo Packages
• Tracing and Profiling
• sysctl
• SysRq Key
• oops Messages
• Kernel Debuggers
• debugfs
• Labs

Scheduling

• Main Scheduling Tasks
• SMP
• Scheduling Priorities
• Scheduling System Calls
• The 2.4 schedule() Function **
• O(1) Scheduler **
• Time Slices and Priorities
• Load Balancing
• Priority Inversion and Priority Inheritance **
• The CFS Scheduler
• Calculating Priorities and Fair Times
• Scheduling Classes
• Scheduler Details
• Labs

Memory Addressing

• Virtual Memory Management
• Systems With and Without MMU and the TLB
• Memory Addresses
• High and Low Memory
• Memory Zones
• Special Device Nodes
• NUMA
• Paging
• Page Tables
• page structure
• Kernel Samepage Merging (KSM) **
• Labs

Huge Pages

• Huge Page Support
• Transparent Huge Pages
• libhugetlbfs
• Labs

Memory Allocation

• Requesting and Releasing Pages
• Buddy System
• Slabs and Cache Allocations
• Memory Pools
• kmalloc()
• vmalloc()
• Early Allocations and bootmem()
• Memory Defragmentation
• Labs

Process Address Space

• Allocating User Memory and Address Spaces
• Locking Pages
• Memory Descriptors and Regions
• Access Rights
• Allocating and Freeing Memory Regions
• Page Faults
• Labs

Disk Caches and Swapping

• Caches
• Page Cache Basics
• What is Swapping?
• Swap Areas
• Swapping Pages In and Out
• Controlling Swappiness
• The Swap Cache
• Reverse Mapping **
• OOM Killer
• Labs

Device Drivers**

• Types of Devices
• Device Nodes
• Character Drivers
• An Example
• Labs

Signals

• What are Signals?
• Available Signals
• System Calls for Signals
• Sigaction
• Signals and Threads
• How the Kernel Installs Signal Handlers
• How the Kernel Sends Signals
• How the Kernel Invokes Signal Handlers
• Real Time Signals
• Labs

Closing and Evaluation Survey

• Evaluation Survey

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