Questions tagged [debugging]

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

Filter by
Sorted by
Tagged with
157
votes
8answers
250k 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 ...
44
votes
2answers
148k views

Running application ends with “Segmentation Fault”

I have a command line application that when run does not do what it is supposed to do and at a certain point leaves the message: Segmentation fault What does this mean? What should I do?
13
votes
3answers
5k views

Is it possible to strace the builtin commands to Bash?

Inspired by this question, titled: When are the built-in commands loaded to memory, while attempting to answer this I tried the following command and was a bit surprised that I couldn't run it: $ ...
83
votes
3answers
111k 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 they are very concrete and contains ...
11
votes
4answers
17k views

How to debug a suspend problem?

I used to have Fedora 14 installed on this HP Compaq 610, and the suspend feature worked fine. Now that I've installed Scientific Linux 6.1 suspend doesn't work anymore. How do I debug/fix it?
169
votes
8answers
335k 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? EDIT: (from ...
55
votes
8answers
70k 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 ...
19
votes
2answers
22k 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 ...
16
votes
2answers
18k views

Can gdb debug suid root programs?

I wrote a program that calls setuid(0) and execve("/bin/bash",NULL,NULL). Then I did chown root:root a.out && chmod +s a.out When I execute ./a.out I get a root shell. However when I do gdb ...
6
votes
1answer
3k views

Defining a state of a failed SD cards by kernel tracing?

I'm having a series of failing/sometimes failing SD cards. They either give one of the following dmesg outputs: The completely dead ones (don't list at /dev/mmcblk0): [ +0,000010] mmc0: error -110 ...
6
votes
2answers
2k views

wpa_supplicant nl80211 hangs linux mint frequently

My Linux Mint system (17 Cinnamon, lenovo g565) hangs up frequently during work (say, 2-4 times a day). It may look different - white screen, black screen, screen freeze. Checking syslog after hangs ...
9
votes
2answers
9k views

How to enable crash reports/core dumps/stack trace logging globally?

Crashing bugs can be the most annoying ones, leading to data loss, downtime and frustrated users. It would be good if applications crashed less. Because of the complexity of the machine context, ...
4
votes
3answers
1k views

Debugging ethernet before NFS boot

I'm trying to boot Linux from U-boot on an embedded ARM board using a filesystem on a remote machine served via NFS. It appears that the ethernet connection is not coming up correctly, which results ...
2
votes
2answers
2k 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 ...
1
vote
1answer
484 views

Is this missing dependency-bug of Python3 in Kazam of Debian 8.5?

I tried to record the bug related to my typing but could not get Kazam work as root and as non-root, see following; I installed it by apt-get install kazam ffmpeg successfully but not properly because ...
8
votes
2answers
2k 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 ...
7
votes
4answers
8k views

Easiest way to find missing quote in a bash a script?

I have a bash script which is currently 700+ lines long. After a particularly long round of editing, it now errors like so: ./run_me.sh: line 693: unexpected EOF while looking for matching `'' ./...
3
votes
1answer
317 views

gdb set overwrite logging on should overwrite gdb.txt correct?

I was looking at Logging Output and had been trying this particular command - set logging overwrite on AFAI understood it, that command is supposed to overwrite the contents of gdb.txt but it does ...
47
votes
5answers
109k views

How to know where a program is stuck in linux?

I am running the following command on my ubuntu server root@slot13:~# lxc-stop --name pavan --logfile=test1.txt --logpriority=trace It seems to hang indefinitely. Whenever this happened on AIX, I ...
30
votes
3answers
6k views

How can I see the exact command line being executed inside some bash instance?

I have a long running bash instance (inside a screen session) that is executing a complex set of commands inside a loop (with each loop doing pipes, redirects, etc). The long command line was ...
8
votes
3answers
5k views

Best practise to diagnose problems [closed]

As Linux/Unix users, we run into problems frequently. And after long hours of problem solving, we develop the skill of debugging. Now, what are good principles, methods or best practises when trying ...
6
votes
2answers
9k views

Is there a GUI debugger for shell scripts

Debugging bash scripts on command line is complicated. Is there a good GUI based debugger available for debugging bash scripts?
4
votes
2answers
12k views

Monodevelop doesn't run the project. When I try to run nothing happens

I've been trying to get Monodevelop up and running for almost a week now, first on my redhat and now on my fedora. The debugger doesn't work, when trying to debug I get this error: I tried re-...
5
votes
2answers
5k views

Install debug flash player in Chrome?

I am trying to adapt the instructions from here, here, and here to install the debug version of the flash player on my Ubuntu 13.04 installation such that Chrome 30.0.1599.66 can use it. ...
1
vote
2answers
6k views

Turning off kASLR to debug linux kernel using qemu and gdb

I'm trying to debug linux kernel using qemu and gdb. The problem is that gdb won't stop at breakpoint. I've searched about it and found that turning kASLR off may help, because kASLR confuses gdb. ...
12
votes
1answer
21k views

ACPI BIOS Error / AE_NOT_FOUND

I'm getting these error messages every single time I reboot my desktop (and a couple of more I don't know how to retain when it's shutting down, but those are not relevant to this question so far): [...
7
votes
1answer
5k views

Can anything useful be done with a truncated core?

We have processes written in a mix of Python, Java and C++ that core dump from time to time. They allocate more memory in chunks as needed during runtime, and are known to crash when their allocation ...
4
votes
2answers
3k views

VirtualBox Error : Kernel Driver not installed(rc=-1908)

I am currently using Ubuntu 18.04 and VirtualBox GUI Version 5.2.18 and I faced the following bug: Kernel driver not installed (rc=-1908) The VirtualBox Linux kernel driver (vboxdrv) is either ...
4
votes
5answers
555 views

Unpredictable memory explosions

The main server at my company has recently been having a lot of downtime. For reasons that neither I nor the other admins can determine, it has random (VERY sudden) explosions in memory. It becomes ...
4
votes
3answers
167 views

Define bash function which does not show up in xtrace (set -x)

In a bash script I have a log() function that is used in several places, as well as a logs() function that diverts lots of line to log(). When I run parts of the script with set -x, obviously all ...
2
votes
2answers
14k 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 ...
2
votes
0answers
733 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 ...
-1
votes
1answer
165 views

Debug an open-source and be confronted with some troubles [closed]

Here is main script . I run it and get some errors like this : ╭─frankwang@ubuntu ~/ion-open-source ╰─➤ ./ionadmin ...
5
votes
1answer
742 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 abort ...
5
votes
2answers
367 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 ...
5
votes
1answer
16k 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? ...
4
votes
2answers
2k views

Shell script debugging

I was wondering if there is an IDE that would allow me to define an ssh connection to a remote host, connect, and locally debug a script running remotely (kind of like you can debug a remote Java app ...
4
votes
2answers
7k 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 ...
2
votes
1answer
873 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
2k 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 ...
1
vote
0answers
278 views

Trace sequence of scripts/commands executed upon ssh

I am executing ssh myuser@myserver. Is there any way to trace all actions performed and the names of files being sourced? (similarly as with bash -x) PS: I executed bash -x at the command prompt ...
0
votes
0answers
26 views

Copying DEB file and install - Error

I build a deb file for Apache2 from its source, also I was able to install and run successfully in the machine which I used to compile. But when I copy(SCP) that deb file to another machine and ...
0
votes
2answers
367 views

frequent linux mint hangs

My Linux Mint system (17 Cinnamon, lenovo g565) hangs up frequently during work (say, 2-4 times a day). It may look different white screen black screen screen freeze Maybe some of these symtoms look ...
0
votes
1answer
13k views

“Failed to complete SSL handshake: NSS error -5938.” while connecting with the retrace server

Having installed Fedora 21 and found that it works very nicely (unless you want dropbox, hardware acceleration in some things, decent video drivers & codecs etc), I have recently turned to ...