is a process of finding and reducing the number of bugs, or defects, in a computer program, thus making it behave as expected
3
votes
1answer
36 views
What exactly is and what does a core dump of process contain?
It's clear that GDB can generate a core dump of process for example via its wrapper - gcore, however it's not clear what exactly it includes and it's really hard to find an answear because different ...
0
votes
1answer
37 views
Why does `w` here require more system calls than a simple python script?
I would like to dive deep into under Linux more and have been playing with a nice tool strace (Version: 4.11) on Ubuntu 16.04 LTS and I am curious as to why call like the following
# strace -c w
...
0
votes
1answer
44 views
How to debug Ubuntu startup process
./Hello!
My Ubuntu 16.04 LTS installation, probably after installing updates, now unable to start Unity after user login. It just freezes! Google'ing won't help this time :/
I.e. OS boots, show ...
1
vote
1answer
24 views
Check if zshrc is being ran/sourced
I am running into an issue where I see command results in .zshrc being displayed twice; in trying to track down the issue I want to know how to check if .zshrc is being run (so I can tell whether it's ...
3
votes
0answers
40 views
/proc/<pid>/fd/1 shows nothing
I'm running ddrescue on my notebook and I'm trying to capture the output in the console from another console. So I tried running
sudo tail -f /proc/<pidOfDdrescue>/fd/1
where "<...
1
vote
1answer
24 views
How can I tell `apt-get update` to download only one file at a time?
I have a machine where apt-get update hangs for ever with a "Waiting for headers" message, suggesting that one source is not responding. From this question I know I can do sudo apt-get -o Debug::...
2
votes
2answers
143 views
Driver for GTX 1080 doesn't work on guest when using KVM PCI Passthrough
I believe we are running into a possible bug with the GTX 1080 (driver) and PCI Passthrough.
My host is an Ubuntu 14.04 system.
My guest is an Ubuntu 14.04/16.04 system (both do the same thing).
I ...
0
votes
0answers
15 views
Unable to Debug on FreeBSD 11.0
I have written a c++ program. But when I try to debug using gdb, it is not able to do so and throws this output.
This GDB was configured as "amd64-marcel-freebsd"...
(gdb) b main
Breakpoint 1 at ...
0
votes
0answers
14 views
Getting vmlinux / debuginfo for an ElRepo Kernel
I recently needed to upgrade my CentOS 7 kernel to something more modern for doing some driver development work.
I am using oprofile to measure a custom kernel module I am developing, so I believe I ...
0
votes
0answers
41 views
asix 3-1:1.0 eth1: kevent 4 may have been dropped
I am using Linux version 3.17.8 with a gumstix.
Linux version 3.17.8 ([email protected]) (gcc version 4.9.1 (GCC) ) #1 SMP Fri Nov 4 18:42:12 EDT6
CPU: ARMv7 Processor [411fc093] revision 3 (...
2
votes
1answer
22 views
Fedora 15 updates
I have a dual booted system, and its been years since I have used the linux side. I am running Fedora15 and am trying to upgrade. I have tried
yum install preupgrade
and I get the error message
...
1
vote
1answer
124 views
Can I track down where a SIGINT came from if it's not from a user?
I have a long running (3 hours) shell script running on a CentOS 7 machine. The script runs a loop with an inner loop and calls curl in each iteration.
I'm starting the script with PM2 because it's ...
0
votes
0answers
12 views
Lightdm spazzing with MATE desktop
After deleting gnome (and gdm3) I needed a new display manager since MATE doesn't have its own stand-alone one. I chose lightdm. It works but not without an extremely annoying graphical bug- when the ...
0
votes
0answers
23 views
How to enable rsyslog debug immediately after bootup
I want to get rsyslog debug logs immediately after bootup. I have RSYSLOG_DEBUG and RSYSLOG_DEBUGLOGS environment variables set, but debugging needs to be turn on with USR1 signal so I need to manualy ...
2
votes
1answer
39 views
why does ltrace produce no output
For several days I have left this command running in a terminal emulator
ltrace -p `pgrep xfwm4`
while using the system normally, and I'm yet to see any output from ltrace. Note: xfwm4 is Xfce's ...
0
votes
0answers
24 views
Change memory allocator behaviour to assist memory corruption debugging / gflags.exe analogue for linux
I'm debugging a memory corruption issue in closed-sourced linux application and, due to it's specifics, nor gdb nor valgrind could help me to trace the root cause - overrun corrupts some thread and ...
2
votes
1answer
172 views
Java equivalent of strace
When I have an issue with a C application, one of the first tools I reach for is strace, I can easily see e.g. if it is blocking on a read from a socket, or for some file I/O or whatever else. But ...
1
vote
0answers
37 views
Debugging a suspend to ram issue with PM_TRACE
So I've been debugging a hairy suspend-to-ram issue, where I get
Oct 12 15:41:23 arjundesktop dbus[2863]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org....
0
votes
0answers
37 views
Linux dynamic kernel debug
Have been working on getting dynamic debug to work on my embedded linux distro by following this guide
https://github.com/tinganho/linux-kernel/blob/master/Documentation/dynamic-debug-howto.txt
But ...
3
votes
1answer
131 views
Record time of every process or thread context switch
I'm trying to get the nearest to real-time processing I can with a Raspbian distribution on a Raspberry Pi for manipulating its GPIO pins. I want to get a "feel" for the kind of performance I can ...
0
votes
1answer
63 views
Run GDB command line multiple times
Due to my mother language is not English. So, excuse me for this bad introduction of my question. I would explain what I need through figure shown below.
As you can see, we have a folder which ...
0
votes
0answers
22 views
good options, arguments to put when using gdb debugger to debug a program?
I am running Debian. Sometimes whenever a program is mis-behaving i.e. crashing I use the following arguments to run gdb on the program. I do have either -dbg or -dbgsym packages installed of the ...
1
vote
1answer
84 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 ...
1
vote
0answers
123 views
Find the cause of a permanently-blocked I/O (process in uninterruptible sleep)
Under Linux, I have a process that is blocked in uninterruptible sleep (state D). How can I investigate what's causing this?
I am running an “ordinary” kernel (a Debian build), without any special ...
0
votes
1answer
365 views
How can I debug Nautilus crashes?
Is there a log file I can peruse, or settings somewhere that might give me a clue?
I'm running GNOME nautilus 3.14.3 ("Files") in Ubuntu 16.04.
2
votes
1answer
120 views
AppArmor is causing Firefox segfaults
I realise this is probably a bad question but I'm stuck. After a lot of googling I'm struggling to fix the problem. I've been trying to get AppArmor to work on Debian. I've been following the ...
0
votes
1answer
660 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 ...
13
votes
2answers
597 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 ...
0
votes
1answer
15 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 ...
2
votes
0answers
31 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 ...
1
vote
0answers
47 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 ...
2
votes
1answer
472 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
=> ...
0
votes
0answers
134 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.
...
1
vote
1answer
71 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
votes
1answer
83 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 ...
1
vote
1answer
116 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 ...
0
votes
0answers
73 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 ...
0
votes
1answer
115 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 ...
1
vote
2answers
47 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
481 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)...
1
vote
0answers
135 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
231 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 ...
1
vote
2answers
108 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:...
4
votes
2answers
1k 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 (...
0
votes
1answer
66 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
2answers
85 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
143 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 ...
2
votes
2answers
395 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 ...
1
vote
0answers
41 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
44 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 ...
