Session
Schedule FOSDEM 2020
Debugging Tools

The elfutils debuginfod server

Debugging data is a necessary evil. It is necessary for running debuggers in situ, some tracing tools, or for coredump analysis. It is evil because it is big - potentially many times the size of the binaries. Therefore, software distributions have conflicting needs to generate & keep this data but not burden everyone with its storage. We will review some degrees of freedom for debugging data distribution, across compiled languages and OS distributions, identifying some of the best practices. We will identify the remaining shortcomings that necessitate exploring yet another way of making debuginfo data available needed. We will present the elfutils debuginfo-server, where a web service offers a lightweight, build-id-indexed lookup of debuginfo-related data on demand. This service is designed to run on a nearby host, private or shared within teams, or even by OS distributions. Clients built into various debugging type tools will be demonstrated.

Additional information

Type devroom

More sessions

2/2/20
Debugging Tools
Marcin Kolny
K.4.201
HawkTracer is low-overhead instrumentation-based profiler built at Amazon Video for platforms with limited capabilities. It's written in C but can be used almost with any other language (we've successfully used it with JavaScript, LUA, Python and Rust). It's highly extensible (at compile time) and portable so it can be run on almost any embedded device. In this talk I'll introduce the architecture of the profiler, present it's advantages and limitations, show how can you instrument the code and ...
2/2/20
Debugging Tools
Matthew Malcomson
K.4.201
We introduce a GDB plugin for working with large data structures in the inferior. This plugin brings some of the flexibility of Unix pipelines to the GDB command prompt, providing the ability to conveniently run some action on every element in a data structure that matches certain criteria. One big aim of this plugin is to make it easy and convenient for a user to write their own sub-commands to iterate over the data structures used in their own program. This is intended for anyone who has found ...
2/2/20
Debugging Tools
Tom Tromey
K.4.201
GDB has had a curses-based interface for many years. Come see what new features are available and how it can improve your debugging experience.
2/2/20
Debugging Tools
Julian Seward
K.4.201
Valgrind's Memcheck tool reports various kinds of errors. One of the most important are those where an if-condition or a memory address uses undefined data. Detecting that reliably on optimized code is challenging, and recent compiler development has made the problem worse.
2/2/20
Debugging Tools
Dmitry Levin
K.4.201
strace is a diagnostic, debugging and instructional utility for Linux. It is used to monitor and tamper with interactions between processes and the Linux kernel, which include system calls, signal deliveries, and changes of process state. In this talk the maintainer of strace will describe new features implemented since FOSDEM 2018.
2/2/20
Debugging Tools
Eugene Syromyatnikov
K.4.201
The talk gives an overview of various optimisations implemented in strace over the past several years. While most of them are quite trivial (like caching of frequently-used data or avoiding syscalls whenever possible), some of them are a bit more tricky (like usage of seccomp BPF programs for avoiding excessive ptrace stops) and/or target more specific use cases (like the infamous thread queueing patch[1], which was carried as a RHEL downstream patch for almost 10 years). [1] ...
2/2/20
Debugging Tools
Paul Chaignon
K.4.201
strace is known to add significant overhead to any application it traces. Even when users are interested in a handful of syscalls, strace will by default intercept all syscalls made by the observed processes, involving several context switches per syscall. Since strace v5.3, the --seccomp-bpf option allows reducing this overhead, by stopping observed processes only at syscalls of interest. This option relies on seccomp-bpf and inherits a few of its limitations. In this talk, we will describe the ...