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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1k views

set -xv behavior in ksh vs bash

Normally I like to have all of the debug output of a script go to a file, so I will have something like: exec 2> somefile set -xv This work very will in bash, but I have noticed in ksh it ...
2
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1answer
9k views

How to debug csh scripts?

My lab uses csh scripts to run jobs. It is usually difficult for me to debug a shell script, so I'm wondering if there is a csh debugger I can use. I know there are some flags like -x or -v that can ...
2
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2answers
769 views

Installing slime and emacs

I'm trying to install SLIME on Fedora 17 so that I can do some lisp. Here is what I downloaded: http://www.common-lisp.net/project/slime/#downloading The CVS Snapshot link. I have a .emacs file: (...
2
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1answer
234 views

How can I figure out why gnome-panel is frequently misbehaving?

On my system (Debian Lenny AMD64), gnome-panel seems to act up now and again. I've not found a way to force it to happen, but it seems to be related to launching processes. Basically, I launch some ...
2
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1answer
55 views

wpa_cli level command always fails

I'm trying to set the debug level of wpa_cli using the level command. It doesn't matter if I use interactive mode or direct commands the level command always fails. wpa_cli -i wlan0 level 1 => ...
2
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1answer
1k 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? ...
2
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1answer
466 views

Best practices for maintaining error logs (system, device driver & application)

I have many Pandaboards with Ubuntu armhf and one PC server networked with Wi-Fi. On each embedded board I have a real-time application running constantly. I don't know how to reasonably maintain the ...
2
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1answer
208 views

“Debugging” with bashdb: why do I lose command echo after stepping into a simple script?

I heard about the bash debugger ( bashdb ) after reading a comment so I thought I should try it out and see if it can help me analyze bash scripts or more generally the execution of commands. There ...
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2answers
64 views

How to tell which files have been created by an application?

I want to find out what files an application has created or modified. In the old days it was easy. cc foo.c created a.out, cc -o foo foo.c created foo, cc -c foo.x created foo.o. Now applications ...
2
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1answer
200 views

sysrq-trigger doesn't accept parameter 'g'

I'm trying to debug the kernel. But I couldn't trigger kgdb with echo g > /proc/sysrq-trigger, it just prints help message. I have enabled kernel debugging, kgdb over serial, frame pointer etc. ...
2
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1answer
793 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 2.6.38-16-...
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1answer
558 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?
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1answer
561 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
173 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
700 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 I'...
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0answers
20 views

separate debug-info files in FreeBSD

In GNU/Linux, there are debug-link and build-id sections in ELF files which shows separate debug-info files name or CRC32 [https://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html]. There ...
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0answers
65 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
277 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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0answers
217 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
141 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 ...
2
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0answers
276 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
142 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 '...
2
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2answers
455 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
516 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
822 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 ...
2
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0answers
65 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 ...
2
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0answers
246 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
1k 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 (...
2
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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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2answers
2k 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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3answers
275 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
49 views

Making sense of Time in dmesg

I know the time in dmesg is the time since boot. But my specific question is this time is calculated at the start or end of the process mentioned in the line? Why this is important? take this example:...
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2answers
43 views

Debugging “unable to connect to sendmail server”

In a corporate environment, we have a mail server which has only ports 25/tcp and 587/tcp available. When we use Perl Scripts (using HTML::Mail) to send hundreds of legitimate mails, it occasional ...
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2answers
639 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
765 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
1k 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
159 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 source:...
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2answers
43 views

Who is stealing my pids?

I noticed that my Debian Jessie system is using many pids, even when the system is (should be) largely idle. The following shows that more or less 270 pids are used per 10s, while the number of active ...
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2answers
4k 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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2answers
473 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
211 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
2k 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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1answer
41 views

2 different libelf.h and libdwarf.h in FreeBSD?

In FreeBSD 10.3 there are 2 libelf.h, /usr/include/libelf.h and /usr/local/include/libelf/libelf.h. And they have different defines, such as enum Elf_Cmd. Also there are 2 libdwarf.h, /usr/include/...
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1answer
85 views

After my system crashed and I run crash, but I get the following error: not a supported file format

My system crashed and even though I haven't been able to know what caused the crash after going through the usual logs: messages, dmesg, secure, etc. There's nothing valuable I have seen on them so I ...
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2answers
110 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
1k 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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1answer
344 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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1answer
586 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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1answer
51 views

Files system become suddently read only; how to debug this?

My ext-4 root and home filesystem became suddently read-only. How can I find out what was the reason for this? The system is ubuntu 16.04 with systemd (installed on an ssd), where root and home ...
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2answers
683 views

Error - Segmentation Fault

I am trying to run DQN, which is some AI for Atari. Upon launching the program (sudo bash run_cpu < the_name_of_the_game >), I get the following error: run_cpu: line 46: 9377 Segmentation ...