This document describes how to debug i3 suitably for sending us useful bug -reports, even if you have no clue of C programming.
First of all: Thank you for being interested in debugging i3. It really means +
This document describes how to debug i3 to send us useful bug +reports, even if you have no knowledge of C programming.
Thank you for being interested in debugging i3. It really means something to us to get your bug fixed. If you have any questions about the -debugging and/or need further help, do not hesitate to contact us!
1. Enabling logging
+1. Verify you are using i3 ⥠4.16.1
i3 logs useful information to stdout. To have a clearly defined place where log -files will be saved, you should redirect stdout and stderr in your -~/.xsession. While youâre at it, putting each run of i3 in a separate log -file with date/time in its filename is a good idea to not get confused about -the different log files later on.
Only the latest major version of i3 is supported. To verify which version +you are running, use:
exec /usr/bin/i3 >~/i3log-$(date +'%F-%k-%M-%S') 2>&1-
To enable verbose output and all levels of debug output (required when -attaching logfiles to bugreports), add the parameters -V -d all, like this:
exec /usr/bin/i3 -V -d all >~/i3log-$(date +'%F-%k-%M-%S') 2>&1+
$ i3 --moreversion 2>&- || i3 --version +Binary i3 version: 4.7 (2013-12-22, branch "tags/4.7") +Running i3 version: 4.7-84-gac74a63 (2014-01-01, branch "next") (pid 1995)
Your version can look like this:
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+
- +4.7 (release version) + +
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+You are using a release version. In many cases, bugs are already +fixed in the development version of i3. Even if the bug is not a known fixed +one, we will still ask you to reproduce your error with the most recent +development version of i3. Therefore, please upgrade to a development version +if you can. +
+
+ - +4.7-85-g9c15b95 (development version) + +
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+Your version is 85 commits newer than 4.7, and the git revision of your +version is 9c15b95. Go to https://github.com/i3/i3/commits/next and see if +the most recent commit starts with the same revision. If so, you are using the +latest version. +
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+
Development versions of i3 have logging enabled by default and are compiled +with debug symbols.
2. Enabling core dumps
+2. Enabling logging
When i3 crashes, often you have the chance of getting a core dump (an image -of the memory of the i3 process which can be loaded into a debugger). To get a -core dump, you have to make sure that the user limit for core dump files is set -high enough. Many systems ship with a default value which even forbids core -dumps completely. To disable the limit completely and thus enable core dumps, -use the following command (in your ~/.xsession, before starting i3):
If you are using a development version (see previous section), you donât need +to do anything — skip to section 3.
If you are using a release version with a custom ~/.xsession (or xinitrc) +file, execute i3 with a line like this:
# Use 25 MiB of RAM for debug logs +exec i3 --shmlog-size=26214400+
If you are NOT using an ~/.xsession file but you just chose "i3" from the +list of sessions in your desktop manager (gdm, lxdm, â¦), edit +/usr/share/xsessions/i3.desktop and replace the Exec=i3 line with:
ulimit -c unlimited+
Exec=i3 --shmlog-size=26214400
Furthermore, to easily recognize core dumps and allow multiple of them, you -should set a custom core dump filename pattern, using a command like the -following:
If you cannot restart i3 for some reason, you can enable debug logging on the +fly:
sudo sysctl -w kernel.core_pattern=core.%e.%p+
i3-msg 'debuglog on; shmlog on; reload'
This will generate files which have the executableâs file name (%e) and the -process id (%p) in it. You can save this setting across reboots using -/etc/sysctl.conf.
3. Compiling with debug symbols
+3. Reproducing the problem
To actually get useful core dumps, you should make sure that your version of i3 -is compiled with debug symbols, that is, that the symbols are not stripped -during the build process. You can check whether your executable contains -symbols by issuing the following command:
Before submitting an issue, please make sure to close down on the problem as +much as you can yourself. Here are some steps you should consider:
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+Find a deterministic, reliable way to reproduce the problem and provide it + with your bug report. +
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+ -
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+Try using the default i3 config to reproduce the problem. If the issue does + not appear with the default config, gradually adapt it to track down what + change(s) to the config introduce the problem. +
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+ -
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+Reproduce the problem with a minimal setup, i.e., only use as few applications, + windows and steps as necessary. +
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+ -
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+In addition, try to stick to applications that are common and, even more + importantly, free / open source. +
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+ -
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+Before obtaining the log file, restart i3 in-place, execute the steps to + reproduce the problem and then save the logs. This keeps the log file as + small as possible and necessary. +
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Please be aware that we cannot support compatibility issues with closed-source +software, as digging into compatibility problems without having access to the +source code is too time-consuming. Additionally, experience has shown that +often, the software in question is responsible for the issue. Please raise an +issue with the software in question, not i3.
4. Obtaining the debug logfile
+
+ Caution
+ |
+
+ Logs may contain sensitive information, so please inspect the log before +submitting it. Logs may be viewed by anyone, once posted. If you choose to +redact the log, make an effort not to discard information which may be relevant +to the issue you are reporting. The best way to avoid submitting such information is to only run the necessary +steps to reproduce the behavior when saving the log file. This will also make +analyzing the log file easier. |
+
No matter whether i3 misbehaved in some way without crashing or whether it just +crashed, the logfile provides all information necessary to debug the problem.
To upload a compressed version of the logfile (for a bugreport), use:
file $(which i3)+
DISPLAY=:0 i3-dump-log | bzip2 -c | curl --data-binary @- https://logs.i3wm.org
You should get an output like this:
This command does not depend on i3 (it also works while i3 displays +the crash dialog), but it requires a working X11 connection.
After running it, you will get a URL to the logfile. Please include that URL in +your bug report.
5. On crashes: Obtaining a backtrace
+When i3 crashes, it will display a dialog stating âi3 just crashedâ, offering +you to save a backtrace to a text file.
To actually get useful backtraces, you should make sure that your version of i3 +is compiled with debug symbols:
/usr/bin/i3: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically +$ file `which i3` +/usr/bin/i3: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped
Notice the not stripped, which is the important part. If you have a version -which is stripped, please have a look if your distribution provides debug +which is stripped, please check whether your distribution provides debug symbols (package i3-wm-dbg on Debian for example) or if you can turn off stripping. If nothing helps, please build i3 from source.
Once you have made sure that your i3 is compiled with debug symbols and the C +debugger gdb is installed on your machine, you can let i3 generate a +backtrace in the crash dialog.
After pressing "b" in the crash dialog, you will get a file called +/tmp/i3-backtrace.%d.%d.txt where the first %d is replaced by i3âs process +id (PID) and the second one is incremented each time you generate a backtrace, +starting at 0.
4. Generating a backtrace
+6. Sending bug reports/debugging on IRC
Once you have made sure that your i3 is compiled with debug symbols and that -core dumps are enabled, you can start making sense out of the core dumps.
Because the core dump depends on the original executable (and its debug -symbols), please do this as soon as you encounter the problem. If you -re-compile i3, your core dump might be useless afterwards.
Please install gdb, a debugger for C. No worries, you donât need to learn it -now. Start gdb using the following command (replacing the actual name of the -core dump of course):
gdb $(which i3) core.i3.3849-
Then, generate a backtrace using:
backtrace full-
When sending bug reports, please attach the whole log file. Even if you think +you found the section which clearly highlights the problem, additional +information might be necessary to completely diagnose the problem.
When debugging with us in IRC, be prepared to use a so-called nopaste service +such as https://pastebin.com because pasting large amounts of text in IRC +sometimes leads to incomplete lines (servers have line length limitations) or +flood kicks.
5. Sending bug reports/debugging on IRC
+7. Debugging i3bar
When sending bug reports, please paste the relevant part of the log (if in -doubt, please send us rather too much information than too less) and the whole -backtrace (if there was a core dump).
When debugging with us in IRC, be prepared to use a so called nopaste service -such as http://nopaste.info or http://pastebin.com because pasting large -amounts of text in IRC sometimes leads to incomplete lines (servers have line -length limitations) or flood kicks.
To debug i3bar problems, use the --verbose commandline parameter, +or add verbose yes to all bar {} blocks in your i3 +config, reload your config and then restart all i3bar instances like this:
$ i3 reload +$ killall i3bar +$ for c in $(i3-msg -t get_bar_config | python -c \ + 'import json,sys;print("\n".join(json.load(sys.stdin)))'); do \ + (i3bar --bar_id=$c >i3bar.$c.log 2>&1) & \ + done;+
There will now be i3bar.*.log files in your current directory that you can provide +in your bug report.