is a process of finding and reducing the number of bugs, or defects, in a computer program, thus making it behave as expected

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1answer
662 views

Resolving executable user stack trace addresses in ftrace

I'm trying to obtain a user stack trace in ftrace, but for some reason, only my user program cannot resolve the addresses to symbols. First, the OS I'm using is: $ uname -a Linux mypc ...
2
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1answer
488 views

How can I run gdb in one machine and run kgdb kernel in another machine?

I want to run two machine: debugged machine: compiled kernel with kgdb option. debugger machine: for running gdb How can I debug machine 1 from machine 2?
2
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1answer
503 views

How can I force my wifi to connect to a G-band channel?

I'm trying to debug a buggy wireless card and would like to force my Linux computer to connect using one of the g-band channels. How can I achieve this?
2
votes
1answer
166 views

Start and stop multiple executable for easy debugging

I'm debugging a networking project, which involves interacting of 3 programs, ie a server, two different clients. However I find it difficult to start and stop them for debugging. Some methods I have ...
2
votes
1answer
587 views

Disable browser logging output to console

I'm currently using Ubuntu 11.04 and I'm running into a really annoying issue while developing for web. I'm rather new to Ubuntu, coming from FreeBSD where I never encountered an issue like this, so ...
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0answers
37 views

Network debugging: Sudden rise in packet loss and latency

My laptop sees a sudden rise in packet loss and latency (from 0.0%, 1ms to 70%, 2000ms). It remains even after resuming from suspend-to-ram. It remains after: sudo killall wpa_supplicant sudo ...
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0answers
29 views

Significance of Linux kernel's default_console_loglevel

What is the significance of default_console_loglevel in Linux? Commonly I see it described as the default value of console_loglevel. However, what that means I haven't seen explained anywhere. ...
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0answers
127 views

How can I monitor the interactions of an application with dbus?

I think the title says it all. I have a set of applications, I want to montior any and all interactions of the applications with dbus. The things I've played with don't seem to have a way of focusing ...
2
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1answer
116 views

m4 macro using variable number of tabs to line up a column

This is the macro I have so far: define(`debug_macro', ` #ifndef $1_DEBUG #define $1_DEBUG'forloop(`i',`1',eval(5-(len($1)/4+ifelse(eval(len($1)%4 == 0)), `0', `1')),` ')dnl`0 #endif ') The goal ...
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0answers
213 views

What is the correct way to fix the configure error: “Requested 'libdrm_nouveau >= 2.4.33' but version of libdrm_nouveau is 0.6”?

This issue came up when trying to assist a user with the questions: What are the required build dependencies of mesa for Debian-based distros? and How do I backport Mesa on Debian Wheezy?. Mesa on ...
2
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1answer
97 views

Why is my Compose key not being passed to Synergy?

The key that I assign to the compose key (right Alt) is not passed to the remote computer by Synergy. I don't know if it's a problem with Synergy or with X, but my guess is that the compose key is ...
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2answers
216 views

How can I remotely debug a broken initrd?

Background I have a system that runs Linux. It's a NAS, and does not have any monitor, keyboard, or serial port. It does have a network port. I'm not happy with the software running on it, and am ...
2
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1answer
382 views

SystemTap simple demo fails

Started learning SystemTap using RedHat's manual. Here is the example I'm trying to run. While executing stap open.stp I got the error: [root@ror6ax ~]# stap open.stp semantic error: while resolving ...
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0answers
628 views

How should I enable the trace log for ALSA hda_unsol_event?

I have reported an ALSA kernel bug and have been asked to "enable tracepoints" and "check the response of hda_unsol_event". I was directed to the kernel docs for instruction, which say: Except ...
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0answers
63 views

kgdb not returning control to gdb

I've compiled a kernel with kgdb support and I'm trying to debug it. I have two machines running, a debug machine (running the kgdb kernel) and the machine I'm using to debug it. They are connected ...
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0answers
207 views

How to find where driver.mod.c links to?

I'm trying to port the webcam composite gadget from kernel 2.6.37 to 2.6.32. I don't have a choice on this since I depend on other drivers and a SDK which only compile for this version. My train of ...
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0answers
950 views

Linux kernel slab usage growing on embedded system

I'm in the process of QA/debugging a project on a custom embedded linux system. The problem we're VERY tight on memory, and even a couple megs can cause issues with our software. What I'm seeing ...
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1answer
1k views

Dump Page table layout (KERNEL CONFIG)

While configuring kernel for debugging found this option: CONFIG_X86_PTDUMP: Export kernel pagetable layout to userspace via debugfs Does this mean RAM page-table layouts ? any guides on how ...
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3answers
246 views

Bash script in ( set -x ) mode does not display what “cat” command does. ( contents of it )

in this bash script.. it simply shows.. +cat as it runs. #!/bin/bash set -x cat > /test << "EOF" a b c d EOF but i rather show everything that it does . including the a b c d ...
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2answers
747 views

Tools for Debugging Routing Tables on a Linux Machine?

Is there a tool that debugs routing tables on a Linux machine? I mean one that I can use by inputting an ip address into it, it'll take the existing routing table into account and output the ...
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2answers
3k views

How to proceed solving ppp connection problems?

I got an embedded system trying to create a ppp connection using a GSM modem. However the connection is never established and all I get is this error message in syslog: Oct 12 08:38:48 pppd[451]: ...
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2answers
394 views

How to call in a kernel level function in user space [closed]

I've developed some helper functions in the kernel. They're called by other functions in the kernel. Currently, they make my custom kernel panic :( For now (i.e. debugging), I made them as a passive ...
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1answer
693 views

Bash option to get resolved executable path?

Bash is able to trace execution script commands with the -x command line option. Each command is then output to stderr, prefixed by PS4 as stated in the man page. -x After expanding each ...
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1answer
817 views

what are some of the best resources to learn advanced debugging techniques using gdb? [closed]

I know the basics of how to use gdb. But I would like to learn some advanced debugging techniques using gdb. What are the best resources - books, blogs, tutorials - that any of you use regularly. I ...
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3answers
152 views

How do I know on which IDE to edit a project's source code?

EDIT: Thanks to all answerers and commenters, there's enough material to keep me busy for a while ! I recently switch to Linux and wanted to do my first development steps with the following ...
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2answers
393 views

Double click Linux Bash Script and debug with pause commands

I'm fairly good with windows .bat scripts and normally use the pause command while developing them so I can see things step by step as the script runs in the command prompt. I am trying to do ...
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2answers
192 views

Why does Linux print a lot of debugging messages on boot/shutdown?

Why does Linux print a lot of debugging messages during the boot and shutdown processes? The boot/shutdown processes usually have no error. Why not hide the debugging messages, and show them only ...
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2answers
1k views

How to “listen” to nginx writes to a file socket

I'm trying to get uwsgi and nginx to play nice. After moving to "file sockets" (hopefully I'm using the right terminology here) from TCP sockets, the only thing I get from uwsgi is a 400 with no ...
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2answers
51 views

How can I disable xtrace and preserve my exit code

I'm trying to figure out a good way to disable xtrace before leaving a script. These are all being executed by Wercker, a continuous integration and deployment SaaS. A previous script of mine has run ...
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1answer
271 views

How to extract running Apache configuration from core dump?

Apache is loading the configuration from files into its memory. If the config files are changing the Apache process won't activate it until a reload/restart happens. Now I have to debug the current ...
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2answers
7k views

How to detect a possible hardware error?

I'm running Debian Wheezy on a HP Pavilion dv7 laptop and it freezes every now and then, requiring a reboot. One time it didn't even load the operating system, but it wasn't I who was using it so I ...
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1answer
523 views

Killed `rm` and `cp` on nfs share

I am just testing an rsnapshot installation on my laptop which should backup to a NAS mounted via nfs on my laptop. On one test rsnapshot died with a cp -al problem (i.e. a problem with hard links) ...
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2answers
2k views

How to compile without optimizations -O0 using CMake?

I am using scientific linux. I am trying to compile a project that uses a bunch of cpp files. In the directory user/project/Build, I enter make to compile and link all the cpp files. I then have to ...
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1answer
1k views

How to avoid overflowing the kernel printk ring buffer?

I'm trying to debug a linux driver and a particular piece of code is behaving very strangely. In order to see what's going on I've filled the code with printk statements so I can see exactly what the ...
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1answer
303 views

Linux, Debugger program development

We are trying to implement the debugger program which will takes either PID or Program name as input and Invoke the gdb by using PID. Below is two small programs are written, Not able to figure out ...
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1answer
2k views

How do I fix a noisy input device (Internal Mic)? snd_hda_intel - debug included

As the title says, I'm having trouble with a very noisy audio input device - the internal mic or any plugged in mics. So far I've narrowed it down to an problem in ALSA since my debug info is showing ...
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1answer
203 views

Is there any way to attach latrace to an already-running process?

I want to trace a running multi-threaded process's library calls. As of 5 November 2012, there's only one way to get ltrace to fully support tracing multi-threaded processes: you must check out and ...
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1answer
4k views

Unprettyfied SSL error message?

I am trying to authenticate using my USB smartcard reader to a website. I am running Ubuntu 10.04 LTS, with its most up to date Firefox browser 3.6.24. I get the following error message: Secure ...
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1answer
101 views

“rcu_preempt detected stalls on CPUs / tasks” message appears to continue

My board continues to display the message below. The terminal does not have any input. What is it with the following message, which I know? (T, g, c, q ...) What is the cause of this phenomenon? ...
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0answers
72 views

Linux Kernel module Remote Debugging with GDB + KGDB, Remote 'g' packet reply is too long

I am trying to remotely debug Linux Kernel and I am having issues. My setup: Target machine with Ubnutu Linux with my custom kernel 4.3 which I built with debugging information and KGDB. ...
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2answers
179 views

viewing printf after pipe (or subshell?)

Ok, this is hard to distill to a single question because it really depends on how I'm going to troubleshoot it. The following script is meant to pipe mount.cifs commands to a while loop that enters ...
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0answers
117 views

ath0 wi-fi connection breaks

Can't hold wi-fi connection in hostapd mode. Sometimes it's good, sometimes not, yesterday all day wi-fi works, today no chance even to connect. % more /etc/rc.conf wlans_ath0="wlan0" ...
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1answer
645 views

How to debug an installed Qt5 library with GDB?

Background: I am programming with Qt5 and want to debug the core Qt5 libraries on Debian using GDB. I have installed all the necessary -dev and -dbg packages. When I try to debug, GDB complains that ...
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0answers
206 views

Transfer file to pc from embedded linux device via serial communications

I'm working on an AT91SAM9G20. I'm connected to AT91SAM9G20 via the debug port using rs232 serial communications. It has Linux version 3.4.8 but does not appear to have any of the common file ...
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1answer
58 views

How to generate a list of configuration files accessed by a tool (eg bash or vi)?

Many times, there are slight inconsistencies between two similar linux machines, where (for example) tmux supports colours on Machine M1, and does not support colours on Machine M2, or vi adds ...
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1answer
203 views

Which log files do I look at to debug copy/paste and Klipper?

Short Version What log files do I look at to monitor copy/paste actions? And what logs do I look at to monitor all Klipper actions? Long Version After using my desktop for a while (could be a few ...
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1answer
190 views

Debugging multiseat: How to run two X server layouts together without display manager?

How to run two X servers together, each with its own layout, directly from command line, without any display manager (e.g. GDB, KDM or LightDM)? Lets say there are two ServerLayout sections in ...
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0answers
450 views

How to display printk messages filtered by level as they come?

I wrote a hello word module that performs a printk when it is loaded in level ALERT and another printk when it is released with level INFO: #include <linux/module.h> #include ...
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0answers
2k views

What does “Cannot make/remove an entry for the specified session” mean?

Instead of logging me in, PAM greets me with the message "Cannot make/remove an entry for the specified session" after I enter the password. What entry is it talking about (and what session)? The ...
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1answer
279 views

What's a good way to debug issues with X forwarding over ssh where just some applications won't run?

As far as I understand it, X forwarding is usually pretty simple. Once I can run some things like xeyes or gimp over ssh, complex applications like firefox/iceweasel should also be able to run. ...