docs/debugging: cover development version, add debugging-release-version
This commit is contained in:
Michael Stapelberg
parent
51728bab77
commit
c3125b4424
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@ -1,7 +1,7 @@
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# To pass additional parameters for asciidoc
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ASCIIDOC=asciidoc
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all: hacking-howto.html debugging.html userguide.html ipc.html multi-monitor.html wsbar.html refcard.pdf testsuite.html
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all: hacking-howto.html debugging.html debugging-release-version.html userguide.html ipc.html multi-monitor.html wsbar.html refcard.pdf testsuite.html
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hacking-howto.html: hacking-howto
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$(ASCIIDOC) -a toc -n $<
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@ -9,6 +9,9 @@ hacking-howto.html: hacking-howto
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debugging.html: debugging
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$(ASCIIDOC) -n $<
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debugging-release-version.html: debugging-release-version
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$(ASCIIDOC) -n $<
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userguide.html: userguide
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$(ASCIIDOC) -a toc -n $<
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139
docs/debugging
139
docs/debugging
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@ -1,7 +1,7 @@
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Debugging i3: How To
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====================
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Michael Stapelberg <michael+i3@stapelberg.de>
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July 2011
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Michael Stapelberg <michael@i3wm.org>
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February 2012
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This document describes how to debug i3 suitably for sending us useful bug
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reports, even if you have no clue of C programming.
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@ -10,100 +10,79 @@ First of all: Thank you for being interested in debugging i3. It really means
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something to us to get your bug fixed. If you have any questions about the
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debugging and/or need further help, do not hesitate to contact us!
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== Enabling logging
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== Verify you are using the latest (development) version
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i3 logs useful information to stdout. To have a clearly defined place where log
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files will be saved, you should redirect stdout and stderr in your
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+~/.xsession+. While you’re at it, putting each run of i3 in a separate log
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file with date/time in its filename is a good idea to not get confused about
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the different log files later on.
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Please verify that you are using the latest version of i3:
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---------------
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$ i3 --version
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i3 version 4.1.2-248-g51728ba (2012-02-12, branch "next")
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---------------
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Your version can look like this:
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4.1.2::
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You are using a release version. Please
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upgrade to a development version first, or read
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link:debugging-release-version[Debugging i3: How To (release version)].
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4.1.2-248-g51728ba::
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Your version is 248 commits newer than 4.1.2, and the git revision of your
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version is +51728ba+. Go to http://code.i3wm.org/i3/commit/?h=next and see if
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the line "commit" starts with the same revision. If so, you are using the
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latest version.
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Development versions of i3 have several properties which make debugging easier:
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1. Shared memory debug logging is enabled by default. You do not have to enable
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logging explicitly.
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2. Core dumps are enabled by default.
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3. If you are using a version from the Debian/Ubuntu autobuilder, it is
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compiled without optimization. Debug symbols are available in the i3-wm-dbg
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package. When compiling i3 yourself, debug mode is the default.
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== Obtaining the debug logfile
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No matter whether i3 misbehaved in some way without crashing or whether it just
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crashed, the logfile provides all information necessary to debug the problem.
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To save a compressed version of the logfile (suitable for attaching it to a
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bugreport), use:
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--------------------------------------------------------------------
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exec /usr/bin/i3 >~/i3log-$(date +'%F-%k-%M-%S') 2>&1
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i3-dump-log | gzip -9c > /tmp/i3.log.gz
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--------------------------------------------------------------------
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To enable verbose output and all levels of debug output (required when
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attaching logfiles to bugreports), add the parameters +-V -d all+, like this:
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This command does not depend on i3 (it also works when i3 currently displays
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the crash dialog), but it requires a working X11 connection. When running it
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from a virtual console (Ctrl-Alt-F1), use:
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--------------------------------------------------------------------
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exec /usr/bin/i3 -V -d all >~/i3log-$(date +'%F-%k-%M-%S') 2>&1
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DISPLAY=:0 i3-dump-log | gzip -9c > /tmp/i3.log.gz
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--------------------------------------------------------------------
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== Enabling core dumps
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== Obtaining a backtrace
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When i3 crashes, often you have the chance of getting a 'core dump' (an image
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of the memory of the i3 process which can be loaded into a debugger). To get a
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core dump, you have to make sure that the user limit for core dump files is set
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high enough. Many systems ship with a default value which even forbids core
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dumps completely. To disable the limit completely and thus enable core dumps,
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use the following command (in your +~/.xsession+, before starting i3):
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When i3 displays its crash dialog, do the following:
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-------------------
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ulimit -c unlimited
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-------------------
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1. Switch to a virtual console (Ctrl-Alt-F1) or login from a different computer
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2. Generate a backtrace (see below)
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3. Switch back to the crash dialog (Ctrl-Alt-F7)
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4. Restart i3 in-place (you will keep your session), continue working
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Furthermore, to easily recognize core dumps and allow multiple of them, you
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should set a custom core dump filename pattern, using a command like the
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following:
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This is how you get a backtrace from a running i3 process:
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---------------------------------------------
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sudo sysctl -w kernel.core_pattern=core.%e.%p
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---------------------------------------------
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This will generate files which have the executable’s file name (%e) and the
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process id (%p) in it. You can save this setting across reboots using
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+/etc/sysctl.conf+.
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== Compiling with debug symbols
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To actually get useful core dumps, you should make sure that your version of i3
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is compiled with debug symbols, that is, that the symbols are not stripped
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during the build process. You can check whether your executable contains
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symbols by issuing the following command:
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----------------
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file $(which i3)
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----------------
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You should get an output like this:
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------------------------------------------------------------------------------
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/usr/bin/i3: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically
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linked (uses shared libs), for GNU/Linux 2.6.18, not stripped
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------------------------------------------------------------------------------
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Notice the +not stripped+, which is the important part. If you have a version
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which is stripped, please have a look if your distribution provides debug
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symbols (package +i3-wm-dbg+ on Debian for example) or if you can turn off
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stripping. If nothing helps, please build i3 from source.
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== Generating a backtrace
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Once you have made sure that your i3 is compiled with debug symbols and that
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core dumps are enabled, you can start making sense out of the core dumps.
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Because the core dump depends on the original executable (and its debug
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symbols), please do this as soon as you encounter the problem. If you
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re-compile i3, your core dump might be useless afterwards.
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Please install +gdb+, a debugger for C. No worries, you don’t need to learn it
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now. Start gdb using the following command (replacing the actual name of the
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core dump of course):
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----------------------------
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gdb $(which i3) core.i3.3849
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----------------------------
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Then, generate a backtrace using:
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--------------
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backtrace full
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--------------
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-----------------
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I3PID=$(pidof i3)
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gdb /proc/$I3PID/exe $I3PID \
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--batch --quiet \
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--ex 'backtrace full' > /tmp/i3-backtrace.txt 2>&1
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-----------------
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== Sending bug reports/debugging on IRC
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When sending bug reports, please paste the relevant part of the log (if in
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doubt, please send us rather too much information than too less) and the whole
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backtrace (if there was a core dump).
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When sending bug reports, please attach the *whole* log file. Even if you think
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you found the section which clearly highlights the problem, additional
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information might be necessary to completely diagnose the problem.
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When debugging with us in IRC, be prepared to use a so called nopaste service
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such as http://nopaste.info or http://pastebin.com because pasting large
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@ -0,0 +1,126 @@
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Debugging i3: How To (release version)
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======================================
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Michael Stapelberg <michael@i3wm.org>
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February 2012
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This document describes how to debug i3 suitably for sending us useful bug
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reports, even if you have no clue of C programming.
|
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|
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First of all: Thank you for being interested in debugging i3. It really means
|
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something to us to get your bug fixed. If you have any questions about the
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debugging and/or need further help, do not hesitate to contact us!
|
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NOTE: This document is for the release version of i3. If you are using a
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development version, please see link:debugging.html[Debugging i3: How To]
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instead.
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== Consider using the development version
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This document is for the release version of i3. In many cases, bugs are already
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fixed in the development version of i3. If they aren’t, we will still ask you
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to reproduce your error with the most recent development version of i3.
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Therefore, please upgrade to a development version and continue reading at
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link:debugging.html[Debugging i3: How To].
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If you absolutely cannot upgrade to a development version of i3, you may
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continue reading this document.
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== Enabling logging
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i3 logs useful information to stdout. To have a clearly defined place where log
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files will be saved, you should redirect stdout and stderr in your
|
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+~/.xsession+. While you’re at it, putting each run of i3 in a separate log
|
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file with date/time in its filename is a good idea to not get confused about
|
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the different log files later on.
|
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|
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--------------------------------------------------------------------
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exec /usr/bin/i3 >~/i3log-$(date +'%F-%k-%M-%S') 2>&1
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--------------------------------------------------------------------
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To enable verbose output and all levels of debug output (required when
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attaching logfiles to bugreports), add the parameters +-V -d all+, like this:
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--------------------------------------------------------------------
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exec /usr/bin/i3 -V -d all >~/i3log-$(date +'%F-%k-%M-%S') 2>&1
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--------------------------------------------------------------------
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== Enabling core dumps
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When i3 crashes, often you have the chance of getting a 'core dump' (an image
|
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of the memory of the i3 process which can be loaded into a debugger). To get a
|
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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
|
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dumps completely. To disable the limit completely and thus enable core dumps,
|
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use the following command (in your +~/.xsession+, before starting i3):
|
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|
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-------------------
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ulimit -c unlimited
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-------------------
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|
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Furthermore, to easily recognize core dumps and allow multiple of them, you
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should set a custom core dump filename pattern, using a command like the
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following:
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|
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---------------------------------------------
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sudo sysctl -w kernel.core_pattern=core.%e.%p
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---------------------------------------------
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This will generate files which have the executable’s file name (%e) and the
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process id (%p) in it. You can save this setting across reboots using
|
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+/etc/sysctl.conf+.
|
||||
|
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== Compiling with debug symbols
|
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|
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To actually get useful core dumps, you should make sure that your version of i3
|
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is compiled with debug symbols, that is, that the symbols are not stripped
|
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during the build process. You can check whether your executable contains
|
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symbols by issuing the following command:
|
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|
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----------------
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file $(which i3)
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----------------
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You should get an output like this:
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------------------------------------------------------------------------------
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/usr/bin/i3: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically
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linked (uses shared libs), for GNU/Linux 2.6.18, not stripped
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------------------------------------------------------------------------------
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Notice the +not stripped+, which is the important part. If you have a version
|
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which is stripped, please have a look if your distribution provides debug
|
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symbols (package +i3-wm-dbg+ on Debian for example) or if you can turn off
|
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stripping. If nothing helps, please build i3 from source.
|
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|
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== Generating a backtrace
|
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|
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Once you have made sure that your i3 is compiled with debug symbols and that
|
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core dumps are enabled, you can start making sense out of the core dumps.
|
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|
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Because the core dump depends on the original executable (and its debug
|
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symbols), please do this as soon as you encounter the problem. If you
|
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re-compile i3, your core dump might be useless afterwards.
|
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|
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Please install +gdb+, a debugger for C. No worries, you don’t need to learn it
|
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now. Start gdb using the following command (replacing the actual name of the
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core dump of course):
|
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|
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----------------------------
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gdb $(which i3) core.i3.3849
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----------------------------
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Then, generate a backtrace using:
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|
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--------------
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backtrace full
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--------------
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== Sending bug reports/debugging on IRC
|
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|
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When sending bug reports, please paste the relevant part of the log (if in
|
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doubt, please send us rather too much information than too less) and the whole
|
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backtrace (if there was a core dump).
|
||||
|
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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.
|
||||
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