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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18
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4answers
2k views

Kernel Hacking Environment

I have been working in embedded OS like uCOS, ThreadX. While I have coded apps in Linux, now I’m planning to start learning Linux Kernel. I have few questions regarding the environment. Which is ...
11
votes
2answers
635 views

Equivalent of “truss -T” and “truss -U” on Linux?

Is there an equivalent of what the -T and -U option of the truss Solaris utility does on Linux. Those are to specify a system call (-T) or library function (-U) which when called by the traced ...
10
votes
5answers
6k 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 ...
10
votes
2answers
496 views

Observing a hard-disk write in kernel space (with drivers/modules)

Apologies in advance if this post is a bit dense/messy, but I'm having a hard time formulating it better... Basically, I would like to study what happens upon a hard disk write, and I'd like to know: ...
10
votes
4answers
3k views

How can I debug a Suspend-to-RAM issue on Linux?

I'm hoping to get experience-based suggestions on how to go about debugging suspend-to-RAM issue. Advice specific to my situation(detailed below) would be great, but I am also interested in general ...
9
votes
2answers
1k views

strace for library calls

I know of strace, which is super handy for watching system calls. Is there an equivalent that can trace calls to external libraries? For example, I'm trying to debug some SSLeay misbehavior with a ...
8
votes
1answer
5k 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?
7
votes
2answers
384 views

How exactly does printk work internally?

I know printf needs help from the OS to do its job. I also know printf does not work in the Linux source code as there is no library. And so we have printk for debugging. How does printk work ...
7
votes
3answers
516 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 ...
7
votes
3answers
5k 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 ...
6
votes
2answers
3k 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?
6
votes
2answers
2k views

How do I debug a kernel module in which a NULL pointer appears?

I have a custom kernel module that I compiled from this patch that adds support for the logitech G19 keyboard among other G series devices. I compiled it just fine against Ubuntu's maverick kernel's ...
6
votes
2answers
302 views

bash: escape individual lines from `-x` echoing

In bash, when running with the -x option, is it possible to exempt individual commands from echoing? I'm trying to make the output as neat as possible, so I am running certain parts of my script in a ...
6
votes
2answers
1k views

How can I find what is interfering with CTRL+F?

I'm running LinuxMint12 with Gnome with Cario-Dock and I have a logitech G15 keyboard. I set up a bash script with the extra keys to take the active window, resize it, and move it to a specific ...
6
votes
1answer
956 views

How to debug system freeze?

I'm experiencing strange bug when I close lid of my laptop - system freezes (no reaction on keys, no response form ssh) hard and displays some strange colour effects. The kernel log (after reboot) ...
6
votes
1answer
144 views

Sending commands to dbx from Vim

Using this information, I've been able to debug code using dbx and display the code from within Vim. What would be really cool is if I could send commands (step, next, print, stop in ... etc) to dbx ...
5
votes
5answers
2k views

How to track/fix a memory-related issue in a large C/C++ code on *nix systems

What strategy you use while tracking a memory-related issue? What tools do you use (open source as well as proprietary) to identify memory leaks, memory corruption etc? How would you track memory ...
5
votes
2answers
267 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: $ ...
5
votes
2answers
995 views

Dump process core without killing the process

Is there a way to get a core dump (or something similar) for a process without actually killing the processes? I have a multithreaded python process running on an embedded system. And I want to be ...
5
votes
1answer
161 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
2answers
308 views

Unclaim a device

So I am using Ubuntu and trying to use some hardware which I had some problems with before. The problem before was that the company who made my hardware sold their internal parts to another company ...
5
votes
0answers
31 views

Is it possible to attach gdb to a crashed process (a.k.a “just-in-time” debugging) [migrated]

When a process crashes I want the possibility to invoke gdb (or a similar debugger) against it in that crashed-but-not-cleaned-up state. Often post-morteming a core dump gives enough information but ...
4
votes
2answers
2k 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 ...
4
votes
4answers
2k views

Debugging Linux machine freezes

I have 15 identical Linux RH 4.7 64-bit severs. They run cluster database (cluster is application level). On occasion (every month or so) a random box (never the same though) freezes. I can ping the ...
4
votes
5answers
418 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
1answer
1k views

What is the difference between /proc/self/stack and output from pstack?

I have been looking through the documentation for /proc and the "stack" object being a new'ish object in proc, I have also looked through the kernel commit to create it -- however the documentation ...
4
votes
2answers
317 views

How to debug an inserted kernel module?

I would like to debug a loaded kernel module I don't have the source code to; I suspect it's a virus. Is there a way to feed it into GDB for analysis?
4
votes
1answer
37 views

Methods to diagnose why an application works for local user account but fails on a network user account?

I have setup a CentOS 6.5 machine that is attached to my company's domain. The OS is configured to allow Active Directory authentication so we do not have to have separate usernames and passwords to ...
4
votes
2answers
2k 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, ...
3
votes
1answer
611 views

How does a debugger work in Linux?

How does a debugger work in Linux? How does it gets 'attached' to an already running executable or process. I understand that compiler translates code to machine language, but then how does debugger ...
3
votes
2answers
263 views

Is there a way to find out which program is segfault-ing?

I have a Busybox/Linux system where a mystery program is segfaulting rarely. Is there a way to find which program is doing this?
3
votes
3answers
603 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 ...
3
votes
4answers
683 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?
3
votes
1answer
437 views

Capture and log GDB backtraces without stopping the process

First, a brief description of the situation: a computer sits hidden near a display in a gallery of some sort, acting as the silent workhorse for a piece. Despite its programmer's best intentions the ...
3
votes
2answers
665 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. ...
3
votes
2answers
2k views

Missing separate debuginfo for - GDB

I have mentioned -g option along with -Wall in the Makefile. When I run gdb onlineSunday, I get: Missing separate debuginfo for /usr/lib64/kde4/plugins/imageformats/kimg_dds.so Try: zypper install ...
3
votes
2answers
421 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 ...
3
votes
1answer
186 views

How to debug a buggy running GUI application?

Suppose the GUI applications are not given names in its GUI, so you don't know what to check in 'ps -A', i.e. the nameless applications in the task bar. How do I know which GUI application belong to ...
3
votes
2answers
614 views

Unix/Linux C++ debugger that supports STL containers?

Currently I am using gcc-4.3.6 and Eclipse IDE for c++ development. I want to debug my project in Eclipse with gdb. I am having a hard time debugging code when it contains STL containers. Also I am ...
3
votes
3answers
1k views

Sound Problems with pulseaudio

The overall question that my whole problem is kind of based on is regarding sound in linux. Should I be using alsa or pulse or what? I'm using pulse at the moment and this is my problem: I was in the ...
3
votes
0answers
60 views

Understanding line numbers reported when using eval

Okay, so I'm stuck working with a shell script that needs to use eval (I know, I know, ultimate evil etc…) however I'm having difficulty debugging some of the line numbers being thrown out by errors. ...
3
votes
1answer
89 views

detect process that executes portscans

I have to administer an ubuntu 12.04 server, where there seem to go portscans to the whole subnet. How can I find out the process that does the scans? pstree init─┬─acpid ...
3
votes
1answer
190 views

How to increase ftrace precision to microseconds?

I'm trying to generate FTrace files inside an Android environment, using: root@adroid:# echo 1 > /sys/kernel/debug/tracing/events/sched/sched_switch/enable root@adroid:# echo 1 > ...
2
votes
2answers
74 views

whats a good tool to search tail -f output

I am dumping some debug info into a text file that I am using tail -f to monitor. Is there a tool that I can then pipe that tail -f data into to be able to search the text on screen using regular ...
2
votes
1answer
84 views

Submitting bug reports for Arch Linux

I come from Ubuntu and when things crashed I could collect the relevant information and submit a bug report. Is there an easy or preferred way to do this in Arch Linux after an application crashes?
2
votes
1answer
78 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 ...
2
votes
4answers
67 views

Is it possible to trace Linux source from initial bootup to desktop-GUI userland code?

I am wondering if, since Linux is 100% open-source, it is possible to follow line-by-line instructions of Linux to observe how the OS works entirely, so that one may get a better knowledge of how OSes ...
2
votes
1answer
243 views

Debugging dmesg logs

I noticed I have the following in my logs. I just am not sure as to how to go about figuring out how to fix or find out what is causing them and if they are serious. [582046.956291] Core dump to ...
2
votes
1answer
1k views

Kernel and QEMU : Unable to mount root fs error

I am trying to run a distro in the virtual disk image with a custom kernel,so that I can experiment and debug the kernel. I followed this to make a disk image and then install Debian to it. Now I ...
2
votes
1answer
3k 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 ...