Debugging and Profiling .NET Core Apps on Linux Sasha Goldshtein Goldshtn CTO, Sela Group Goldshtn the Plan
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Introduction to Debugging the Freebsd Kernel
Introduction to Debugging the FreeBSD Kernel John H. Baldwin Yahoo!, Inc. Atlanta, GA 30327 [email protected], http://people.FreeBSD.org/˜jhb Abstract used either directly by the user or indirectly via other tools such as kgdb [3]. Just like every other piece of software, the The Kernel Debugging chapter of the FreeBSD kernel has bugs. Debugging a ker- FreeBSD Developer’s Handbook [4] covers nel is a bit different from debugging a user- several details already such as entering DDB, land program as there is nothing underneath configuring a system to save kernel crash the kernel to provide debugging facilities such dumps, and invoking kgdb on a crash dump. as ptrace() or procfs. This paper will give a This paper will not cover these topics. In- brief overview of some of the tools available stead, it will demonstrate some ways to use for investigating bugs in the FreeBSD kernel. FreeBSD’s kernel debugging tools to investi- It will cover the in-kernel debugger DDB and gate bugs. the external debugger kgdb which is used to perform post-mortem analysis on kernel crash dumps. 2 Kernel Crash Messages 1 Introduction The first debugging service the FreeBSD kernel provides is the messages the kernel prints on the console when the kernel crashes. When a userland application encounters a When the kernel encounters an invalid condi- bug the operating system provides services for tion (such as an assertion failure or a memory investigating the bug. For example, a kernel protection violation) it halts execution of the may save a copy of the a process’ memory current thread and enters a “panic” state also image on disk as a core dump. -
Process and Memory Management Commands
Process and Memory Management Commands This chapter describes the Cisco IOS XR software commands used to manage processes and memory. For more information about using the process and memory management commands to perform troubleshooting tasks, see Cisco ASR 9000 Series Aggregation Services Router Getting Started Guide. • clear context, on page 2 • dumpcore, on page 3 • exception coresize, on page 6 • exception filepath, on page 8 • exception pakmem, on page 12 • exception sparse, on page 14 • exception sprsize, on page 16 • follow, on page 18 • monitor threads, on page 25 • process, on page 29 • process core, on page 32 • process mandatory, on page 34 • show context, on page 36 • show dll, on page 39 • show exception, on page 42 • show memory, on page 44 • show memory compare, on page 47 • show memory heap, on page 50 • show processes, on page 54 Process and Memory Management Commands 1 Process and Memory Management Commands clear context clear context To clear core dump context information, use the clear context command in the appropriate mode. clear context location {node-id | all} Syntax Description location{node-id | all} (Optional) Clears core dump context information for a specified node. The node-id argument is expressed in the rack/slot/module notation. Use the all keyword to indicate all nodes. Command Default No default behavior or values Command Modes Administration EXEC EXEC mode Command History Release Modification Release 3.7.2 This command was introduced. Release 3.9.0 No modification. Usage Guidelines To use this command, you must be in a user group associated with a task group that includes appropriate task IDs. -
Post Mortem Crash Analysis
Post Mortem Crash Analysis Johan Heander & Magnus Malmborn January 14, 2007 Abstract To improve the quality and reliability of embedded systems it is important to gather information about errors in units already sold and deployed. To achieve this, a system for transmitting error information from the customer back to the developers is needed, and the developers must also have a set of tools to analyze the error reports. The purpose of this master thesis was to develop a fully functioning demon- stration system for collection, transmission and interpretation of error reports from Axis network cameras using the Linux operating system. The system has been shown to handle both kernel and application errors and conducts automatic analysis of received data. It also uses standard HTTP protocol for all network transfers making it easy to use even on firewalled net- works. i ii Acknowledgement We would like to thank our LTH supervisor Jonas Skeppstedt for all he has taught us about computer science in general and operating systems and the C programming language in particular. We would also like to thank Mikael Starvik at Axis Communications for quickly providing us with all hardware and information we needed to complete this thesis, and for providing us with support during our implementation and writing. Finally we thank all the developers working at Axis Communications, many of whom have provided input and reflections on our work. iii iv Contents 1 Introduction 1 1.1 Problem description . 1 1.2 Problem analysis . 1 2 Background 3 2.1 Kernel crashes . 3 2.2 User space crashes . -
Challenges in Debugging Dynamically Compiled Languages As Exemplified by C# Debugger for Tizen
Samsung R&D Institute Russia Center of System Software Challenges in debugging dynamically compiled languages as exemplified by C# debugger for Tizen Dmitri Botcharnikov 1 Agenda Dynamically compiled languages Tizen .NET Debugging Challenges Tizen .NET Debugger internals Future plans 2 Dynamically compiled languages Dynamically (Just-In-Time) compiled languages VM manages low-level details: memory allocation, exception handling But for debuggers… 3 Tizen .NET Visual Studio Tools for Tizen preview were released C# was added to Tizen Over 1,400,000 C# developers worldwide Tizen running on 50 millions Samsung devices (TV, wearables, mobile, IoT) http://developer.tizen.org 4 Technologies Tizen OS (emulator, platform-specific APIs) Xamarin.Forms .NET Core (CoreCLR, CoreFX, Roslyn) Visual Studio 2015 (Windows) 5 C# Compilation & Execution C# source MSIL Output CLR Roslyn JIT Language-specific compiler: C# => MSIL CLR JIT compiler: MSIL => native code 6 Debugging Challenges Source code to native code mapping ◦ C# compiler generates debugging information for source code to MSIL mapping Stepping in and over ◦ Stepping into not yet compiled code ◦ Managed exception handlers ◦ Lambdas, closures & iterators Local variables & arguments inspection ◦ C# compiler generates debugging information for MSIL variables 7 LLDB Subproject of LLVM (http://lldb.llvm.org) Native debugger builds on LLVM and Clang libraries Supports X86 and ARM architectures 8 SOS debugger plug-in Plug-in for LLDB (libsosplugin.so, libsos.so) Port of SOS.dll -
Visual Studio Team Test Quick Reference a Quick Reference for Users of the Team Testing Features of Visual Studio Team System
MICROSOFT Visual Studio Team Test Quick Reference A quick reference for users of the Team Testing features of Visual Studio Team System Geoff Gray and the Microsoft VSTS Rangers team 3/30/2009 VSTS Rangers This content was originally created by Geoff Gray for internal Microsoft use and then adopted and expanded as a Visual Studio Team System (“VSTS”) Rangers project. “Our mission is to accelerate the adoption of Team System by delivering out of band solutions for missing features or guidance. We work closely with members of Microsoft Services to make sure that our solutions address real world blockers.” -- Bijan Javidi, VSTS Rangers Lead Copyright 2009 Microsoft Corporation Page | 1 Summary This document is a collection of items from public blog sites, Microsoft® internal discussion aliases (sanitized) and experiences from various Test Consultants in the Microsoft Services Labs. The idea is to provide quick reference points around various aspects of Microsoft Visual Studio® Team Test edition that may not be covered in core documentation, or may not be easily understood. The different types of information cover: How does this feature work under the covers? How can I implement a workaround for this missing feature? This is a known bug and here is a fix or workaround. How do I troubleshoot issues I am having? The document contains two Tables of Contents (high level overview, and list of every topic covered) as well as an index. The current plan is to update the document on a regular basis as new information is found. The information contained in this document represents the current view of Microsoft Corporation on the issues discussed as of the date of publication. -
LLDB Tutorial: Adding Debugger Support for Your Target LLVM 2016 Tutorial
LLDB Tutorial: Adding debugger support for your target LLVM 2016 tutorial Deepak Panickal Andrzej Warzyński Codeplay Soware @codeplayso March 18, 2016 Outline • LLDB architecture crash course I Overview of LLDB I User scenarios such as breakpoints, stack-walking etc. I Debugging ps • Both generic and specialized architectures are covered I MSP430 lldb debugging, which we have implemented for this tutorial I github.com/codeplaysoftware/lldb-msp430 I ARM architecture is also referred to for the generic cases • Focusing on debugging ELF executables on Linux EuroLLVM 2016 Outline 2 / 54 Overview Part 1: The Basics Part 2: ELF And Architecture Support Part 3: Registers Part 4: Memory and Breakpoints Part 5: Other Key Features Part 6: Debugging Tips Part 7: MSP430 Quick Recap EuroLLVM 2016 Outline 3 / 54 Part 1 The Basics EuroLLVM 2016 Part 1: The Basics 4 / 54 LLDB - Architecture lldb user driver TCP Socket GDB RSP . lldb-server debug API Architecture of LLDB LLDB offers mulple opons: I user drivers: command line, lldb-mi, Python I debug API: ptrace/simulator/runme/actual drivers EuroLLVM 2016 Part 1: The Basics 5 / 54 lldb/lldb-server lldb • Runs on host • Interacts with the user • Understands symbols, DWARF informaon, data formats, etc. • Plugin architecture I ProcessGDBRemote, DynamicLoaderPOSIXDYLD, ABISysV_msp430 are some... lldb-server • Runs on both remote and host, communicates to lldb via RSP over whichever medium is available • Interacts with the hardware/simulator • Deals with binary data and memory addresses • Plugin architecture I ObjectFileELF, ProcessLinux, are some... EuroLLVM 2016 Part 1: The Basics 6 / 54 GDB Remote Serial Protocol • Simple, ASCII message based protocol • Designed for debugging remote targets • Originally developed for gdb<->gdbserver communicaon • Extended for LLDB, see lldb-gdb-remote.txt Packet structure: checksum $. -
Download Full CV (PDF)
Full name : Lars Bjergner Mikkelsen. Practical experience: Company name: LARSMIKKELSEN.COM Aps Street & number: Husoddebakken 26 City: Horsens Zip code: 8700 Country: Denmark. Web address: http://www.larsmikkelsen.com Start date of employment: 27-July-2007. End date of employment: Not ended Job title: Owner at LARSMIKKELSEN.COM Aps. Job description: Freelance specialist Microsoft Dynamics Ax and .NET. Technical solution architect Dynamics Ax projects. Development in x++ and C#. Integration specialist between Dynamics Ax and .NET on several projects. SharePoint Enterprise Portal solutions on Dynmaics Ax 4.0 and ASP.NET based Dynamics Ax 2009 solution. Invented, designed and developed Advanced Ax Batch. Advanced Ax Batch is a Dynamics Ax and .NET based scheduler which are used by several companies for batch execution in Dynamcis Ax. Performance optimization Dynamics Ax solutions. Specialized knowledge: Highly experienced with performance optimization and trouble shooting of Dynamics Ax installations. Technologies mastered: Programming Languages (X++, C#) Programming Libraries (Axapta, .NET Framework) Component Technology (Axapta, .NET , COM, COM+, Active X) Databases (SQL server) Markup Languages (HTML, XML) Internet (SharePoint Enterprise Portal) Development tools (Axapta, Visual studio .NET) Protocols (HTTP, SOAP, TCP/IP) 1 Company name: Columbus IT Street & number: 3151 Airway, Building N-1 City: Costa Mesa, CA Zip code: 8240 Country: USA. Web address: http://www.columbusit.com Start date of employment: 23-May-2005. End date of employment: 27-July-2007. Job title: Technology / integration manager and solution architect. Job description: Responsible for technology and integration strategies. Technical solution architect on major Dynamics Ax projects. Development in x++ and C#. Technical responsible for worldwide mobility platform. -
Linux Core Dumps
Linux Core Dumps Kevin Grigorenko [email protected] Many Interactions with Core Dumps systemd-coredump abrtd Process Crashes Ack! 4GB File! Most Interactions with Core Dumps Poof! Process Crashes systemd-coredump Nobody abrtd Looks core kdump not Poof! Kernel configured Crashes So what? ● Crashes are problems! – May be symptoms of security vulnerabilities – May be application bugs ● Data corruption ● Memory leaks – A hard crash kills outstanding work – Without automatic process restarts, crashes lead to service unavailability ● With restarts, a hacker may continue trying. ● We shouldn't be scared of core dumps. – When a dog poops inside the house, we don't just `rm -f $poo` or let it pile up, we try to figure out why or how to avoid it again. What is a core dump? ● It's just a file that contains virtual memory contents, register values, and other meta-data. – User land core dump: Represents state of a particular process (e.g. from crash) – Kernel core dump: Represents state of the kernel (e.g. from panic) and process data ● ELF-formatted file (like a program) User Land User Land Crash core Process 1 Process N Kernel Panic vmcore What is Virtual Memory? ● Virtual Memory is an abstraction over physical memory (RAM/swap) – Simplifies programming – User land: process isolation – Kernel/processor translate virtual address references to physical memory locations 64-bit Process Virtual 8GB RAM Address Space (16EB) (Example) 0 0 16 8 EB GB How much virtual memory is used? ● Use `ps` or similar tools to query user process virtual memory usage (in KB): – $ ps -o pid,vsz,rss -p 14062 PID VSZ RSS 14062 44648 42508 Process 1 Virtual 8GB RAM Memory Usage (VSZ) (Example) 0 0 Resident Page 1 Resident Page 2 16 8 EB GB Process 2 How much virtual memory is used? ● Virtual memory is broken up into virtual memory areas (VMAs), the sum of which equal VSZ and may be printed with: – $ cat /proc/${PID}/smaps 00400000-0040b000 r-xp 00000000 fd:02 22151273 /bin/cat Size: 44 kB Rss: 20 kB Pss: 12 kB.. -
The Complete Freebsd
The Complete FreeBSD® If you find errors in this book, please report them to Greg Lehey <grog@Free- BSD.org> for inclusion in the errata list. The Complete FreeBSD® Fourth Edition Tenth anniversary version, 24 February 2006 Greg Lehey The Complete FreeBSD® by Greg Lehey <[email protected]> Copyright © 1996, 1997, 1999, 2002, 2003, 2006 by Greg Lehey. This book is licensed under the Creative Commons “Attribution-NonCommercial-ShareAlike 2.5” license. The full text is located at http://creativecommons.org/licenses/by-nc-sa/2.5/legalcode. You are free: • to copy, distribute, display, and perform the work • to make derivative works under the following conditions: • Attribution. You must attribute the work in the manner specified by the author or licensor. • Noncommercial. You may not use this work for commercial purposes. This clause is modified from the original by the provision: You may use this book for commercial purposes if you pay me the sum of USD 20 per copy printed (whether sold or not). You must also agree to allow inspection of printing records and other material necessary to confirm the royalty sums. The purpose of this clause is to make it attractive to negotiate sensible royalties before printing. • Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one. • For any reuse or distribution, you must make clear to others the license terms of this work. • Any of these conditions can be waived if you get permission from the copyright holder. Your fair use and other rights are in no way affected by the above. -
Exniffer: Learning to Rank Crashes by Assessing the Exploitability from Memory Dump
Exniffer: Learning to Rank Crashes by Assessing the Exploitability from Memory Dump Thesis submitted in partial fulfillment of the requirements for the degree of MS in Computer Science & Engineering by Research by Shubham Tripathi 201407646 [email protected] International Institute of Information Technology Hyderabad - 500 032, INDIA March 2018 Copyright c Shubham Tripathi, March 2018 All Rights Reserved International Institute of Information Technology Hyderabad, India CERTIFICATE It is certified that the work contained in this thesis, titled “Exniffer: Learning to Rank Crashes by Assessing the Exploitability from Memory Dump” by Shubham Tripathi, has been carried out under my supervision and is not submitted elsewhere for a degree. Date Adviser: Prof. Sanjay Rawat “Contemplate and reflect upon knowledge, and you will become a benefactor to others.” To my parents Acknowledgments I would like to express my gratitude to my adviser, Dr. Sanjay Rawat. Sanjay sir helped me staying focused on problems and provided new directions to approach them. Working with him, I have devel- oped my problem solving skills, learnt about research, about life in general. I would be thankful to him for all my life, for providing me the guidance on various matters, always motivating and boosting me with confidence, which really helped me in shaping my life. I must also thank all my lab-mates who are working or have worked earlier in CSTAR - Vijayendra, Spandan, Satwik, Charu, Teja, Ishan and Lokesh. I really enjoyed working with them in the lab. I would like to thank all my friends in IIIT, for making my stay in the campus a memorable one. -
Chapter 2: Operating-System Structures
Chapter 2: Operating-System Structures Operating System Concepts – 10th Edition Silberschatz, Galvin and Gagne ©2018 Chapter 2: Operating-System Structures Operating System Services User and Operating System-Interface System Calls System Services Linkers and Loaders Why Applications are Operating System Specific Operating-System Design and Implementation Operating System Structure Building and Booting an Operating System Operating System Debugging Operating System Concepts – 10th Edition 2.2 Silberschatz, Galvin and Gagne ©2018 Objectives Identify services provided by an operating system Illustrate how system calls are used to provide operating system services Compare and contrast monolithic, layered, microkernel, modular, and hybrid strategies for designing operating systems Illustrate the process for booting an operating system Apply tools for monitoring operating system performance Design and implement kernel modules for interacting with a Linux kernel Operating System Concepts – 10th Edition 2.3 Silberschatz, Galvin and Gagne ©2018 Operating System Services Operating systems provide an environment for execution of programs and services to programs and users One set of operating-system services provides functions that are helpful to the user: User interface - Almost all operating systems have a user interface (UI). Varies between Command-Line (CLI), Graphics User Interface (GUI), touch-screen, Batch Program execution - The system must be able to load a program into memory and to run that program, end execution, either normally or abnormally (indicating error) I/O operations - A running program may require I/O, which may involve a file or an I/O device Operating System Concepts – 10th Edition 2.4 Silberschatz, Galvin and Gagne ©2018 Operating System Services (Cont.) One set of operating-system services provides functions that are helpful to the user (Cont.): File-system manipulation - The file system is of particular interest. -
Microsoft SQL Server Analysis Services Multidimensional Performance and Operations Guide Thomas Kejser and Denny Lee
Microsoft SQL Server Analysis Services Multidimensional Performance and Operations Guide Thomas Kejser and Denny Lee Contributors and Technical Reviewers: Peter Adshead (UBS), T.K. Anand, KaganArca, Andrew Calvett (UBS), Brad Daniels, John Desch, Marius Dumitru, WillfriedFärber (Trivadis), Alberto Ferrari (SQLBI), Marcel Franke (pmOne), Greg Galloway (Artis Consulting), Darren Gosbell (James & Monroe), DaeSeong Han, Siva Harinath, Thomas Ivarsson (Sigma AB), Alejandro Leguizamo (SolidQ), Alexei Khalyako, Edward Melomed, AkshaiMirchandani, Sanjay Nayyar (IM Group), TomislavPiasevoli, Carl Rabeler (SolidQ), Marco Russo (SQLBI), Ashvini Sharma, Didier Simon, John Sirmon, Richard Tkachuk, Andrea Uggetti, Elizabeth Vitt, Mike Vovchik, Christopher Webb (Crossjoin Consulting), SedatYogurtcuoglu, Anne Zorner Summary: Download this book to learn about Analysis Services Multidimensional performance tuning from an operational and development perspective. This book consolidates the previously published SQL Server 2008 R2 Analysis Services Operations Guide and SQL Server 2008 R2 Analysis Services Performance Guide into a single publication that you can view on portable devices. Category: Guide Applies to: SQL Server 2005, SQL Server 2008, SQL Server 2008 R2, SQL Server 2012 Source: White paper (link to source content, link to source content) E-book publication date: May 2012 200 pages This page intentionally left blank Copyright © 2012 by Microsoft Corporation All rights reserved. No part of the contents of this book may be reproduced or transmitted in any form or by any means without the written permission of the publisher. Microsoft and the trademarks listed at http://www.microsoft.com/about/legal/en/us/IntellectualProperty/Trademarks/EN-US.aspx are trademarks of the Microsoft group of companies. All other marks are property of their respective owners.