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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26 views

How to step-into, step-over and step-out with GDB?

I typed help while I was in the GDB but didn't find anything about step-into, step-over and step-out. I put a breakpoint in an Assembly program in _start (break _start). Afterwards I typed next and it ...
11
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2answers
427 views

Is there a way for shell script to know which program has executed it?

In *nix world, is there a way for shell script to have information about which program has executed it? Example: /path/to/script1 /path/to/script_xyz in this imaginary scenario, script_xyz would ...
24
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3answers
39k views

Linux network troubleshooting and debugging

From time to time Linux and Unix users faced with various network problems. Many of these problems are presented here and at some others troubleshooting forums, but the are very concrete and contains ...
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0answers
38 views

Process crashed on the first several times when launching

I use OpenWrt and build OpenWrt provided Python 2.7.9 as modules which are standalone .ipk files. I simply copy those ipk files to our MIPSel platform and install it to a mounted file system on eMMC. ...
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1answer
42 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/...
3
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1answer
1k views

My Debian freezes

I installed a fresh Debian 7 install, but it freezes from time to time, and when it happens (quite often indeed) only the mouse can move around but everything is blocked. All I can do is restart. I ...
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0answers
12 views

Debug CalDAVs sync failures with network sniffer, how to be display prettyprinted traffic in terminal

I need to debug some unsuccessful CalDAV synchronization requests. I have functioning clients, so I can compare working vs broken. The traffic is SSL-encrypted, but I have the key. I have root on a ...
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1answer
2k views

How do I get debug information from rsyslog?

I followed the directions from: http://www.rsyslog.com/doc/debug.html I put the following in /etc/rsyslog.conf: $DebugLevel 2 $DebugFile /root/RSYSLOG.txt then I try: kill -USR1 `cat /var/run/...
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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
26 views

list of wpa_supplicant error messages

I'm trying to write a test to debug a network manager that utilises wpa_supplicant but I'm having a hard time finding a list of error messages that I can expect for CTRL-EVENT-SSID-TEMP-DISABLED ...
0
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1answer
57 views

How can I display \n as new lines in multitail?

I am using multitail to monitor logs while I program. I really like this tool. However, it is hard to use it to view object output in a php error log because new line characters \n are not processed. ...
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 => ...
4
votes
1answer
363 views

Source code location for debugging on Debian?

From Debian's DebugPackage, I know the debug information file for an executable goes in /usr/lib/debug when creating two part executables (i.e., stripping the executable of its symbols and placing ...
3
votes
1answer
29 views

bash: Cancelling the execution of 'trap handler DEBUG'

I can get a function myHandler() to execute before a bash command by doing the following: function myHandler() { ... } trap 'myHandler' DEBUG However, I'd like to be able to proceed with or ...
1
vote
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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0answers
27 views

controlling wpa_supplicant using node.js

I would like to control wpa_supplicant using a node.js module. Most importantly I want to be able to detect connection failures so I can write a program that can act upon them. So far setting up a ...
3
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0answers
192 views

An obscure autotools error with Epson iscan project

I'm seeing the following error when attempting to build iscan using the master branch on Debian wheezy. This project provides support for Epson scanners, in cases when SANE doesn't. This project ...
0
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1answer
38 views

Generic debugging / logging / tracing filesystem directory & file access? [duplicate]

This is my particular problem: I'm trying to set up git on a server, for which I'm doing a test on a locally installed apache on Ubuntu 14.04; for instance, I can do git clone fine over HTTP, but git ...
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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 ...
1
vote
0answers
138 views

How to enable kernel pstore?

I'm trying to enable the kernel persistent storage (pstore) in order to help debug a module which malfunctions and freezes my laptop on suspend, but I'm having difficulties doing so. My kernel (4.1.20)...
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0answers
43 views

How to let kernel not run the printk with KERN_DEBUG

I noticed that kernel has different console levels for the printk. I also noticed this post [1]. I understand that we can change the /proc/sys/kernel/printk to change the printk level for the ...
3
votes
2answers
62 views

How can I activate extra-verbose mode (debugging mode) during Debian boot?

How do I activate extra verbosity during boot, on Debian? I removed the quiet parameter and tried to add debug but it didn't help. My problem is that my keyboard takes 2-3 min to activate so it ...
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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
5k views

How can we trace problems of crashing programs in Linux?

If an application crashes in Windows we can check the Event Viewer in the Administration tools to see what has crashed. Sometimes it has useful information others not, but it is a start. In linux if ...
4
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2answers
374 views

Understanding wpa_supplicant

TL;DR. I need help getting to the bottom of: why there are errors related to ioctl when using wext driver, why I'm not able to use nl80211 driver. When running wpa_supplicant I get weird errors ...
5
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2answers
2k views

Where is vagrant's log file?

I am trying to debug a vagrant- or VirtualBox related problem (see taiga-vagrant fails to provide a working taiga environment #21). The command VAGRANT_LOG=debug vagrant up --debug prints out plenty ...
2
votes
2answers
174 views

Debugging a kernel shut down?

I'm on Linux 4.2.0, the Ubuntu Wily HWE kernel for Ubuntu 14.04 (which is what I'm running). There's a nasty bug on MacBook 11,4 and 11,5 models where the laptops won't actually ever shut off, they ...
26
votes
6answers
24k views

Can we get compiler information from an elf binary?

Is there some chance to know how a binary was built, under Linux? (and or other Unix) Compiler, version, time, flags etc... I looked at readelf and couldn't find much, but there might be other ways ...
0
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1answer
22 views

Storing PHP output issued by crontab

I have a PHP file that is suppose to send one email per day scheduled by crontab. Here is my crontab: 45 23 * * * php /var/www/html/linus/class/runnable/dailyStaffReport.php I noticed that it's not ...
1
vote
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 ...
1
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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 ...
3
votes
1answer
70 views

How to dump the dmesg AKA Kernel logs to a single .txt file from the kernel boot?

I am trying to understand the SATA Host-Device Communication and for that I have put a lot of debug messages in the kernel driver code. Now messages are in such a huge amount that I am not able to see ...
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4answers
30k views

How to view core files for debugging purposes in Linux?

I want to view the contents of a core file while debugging a program. How can I view the contents of a core file?
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0answers
33 views

How to debug a bash script in a qemu-arm chroot

I'm running a debian debootstrap script which creates an arm system. However, the script fails at some point and the error message does not really help. So I'll have to do some more debugging which is ...
0
votes
1answer
30 views

Why is echo not working for mt valgrind command?

So I have my makefile working great, except that It doesn't create the valgrind.out file and I don't know why. So the console succesfully prints out that my executable file line is created but not ...
50
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7answers
34k views

How to debug a bash script?

I'm having some problems with some scripts in bash, about errors and unexpected behaviors. I would like to investigate the causes of the problems so I can apply fixes. Is there a way I can turn some ...
5
votes
1answer
1k views

Debugging Linux Kernel with QEMU

I was trying to study the debugging of kernel using QEMU. I tried initially and failed due to the fact that there was no virtual file system. The answers to this post suggests that there should be a ...
2
votes
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
votes
1answer
153 views

Inline debug (xtrace) in scripts

Is there a way to force enable or disable debug (xtrace) per command line in scripts ? In Windows Shell ("ms-dos") is an "@" which can prefix a command line, disabling that line to be showed if the ...
0
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0answers
23 views

Does Manjaro Linux have a debug packages

One of my biggest frustrations with Arch Linux is the need to recompile half my OS every few weeks in order to provide meaningful bug reports to upstream projects. Most other distributions provide ...
1
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0answers
244 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. ...
0
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1answer
59 views

Debugging: OwnCloud horribly slow

I am trying to figure out why my OwnCloud installation stalls of 10s of seconds before it runs again for 10s of seconds normally. What kind of debugging can I enable on OwnCloud (server+client), so I ...
6
votes
2answers
363 views

Debugging lock-up - systemd loses my logs

Ever since I have "upgraded" to systemd on Arch Linux, I keep losing logs when an unexpected lockup happens. I hit the same log-losing issue one month ago and just hit the issue again. There are also ...
5
votes
1answer
255 views

linux mint hangs - how to find a reason?

My Linux Mint system (17 Cinnamon, lenovo g565) hangs up frequently during work (say, 2-4 times a day). It usually looks like a white or black screen (or off if the lid was closed). CPU seems to be a ...
0
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0answers
64 views

printk does not prints in terminal

I inserted some printk in kernel 3.15.1 functions such as theese: in fs/read_write.c in function read(): printk("Ata: Im in fs/read_write.c and in function read"); in same file in function ...
8
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1answer
186 views

Tool to trace library calls in Linux/ARM

I am searching for a tool that allows to trace calls to functions in shared libraries in Linux/ARM. Basically, I want to be able to specify a command line and let this tool produce a record of called ...
0
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1answer
115 views

Syntax error: Unterminated quoted string. Cannot find error

I'm writing a script to parse a larger file into usable data. I will attach the script below. The script was not running as I wanted and I thought it might have been the if/then statement I used, but ...
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0answers
64 views

OpenVPN Connection without disabling Internet debugging

I've recently configured OpenVPN on my server (CentOS 7) and been configuring it for hours now and everything seems to work fine except that when I connect using a client machine I cannot access the ...
1
vote
1answer
87 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 ...
19
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3answers
29k views

how can I make cron run a job right now, for testing/debugging? without changing the schedule!

I have a cron job that is scheduled to run everyday, other than changing the schedule, is there any other way to do a test run of the command right now to see if it works as intended?