diff --git a/docs/debugging b/docs/debugging index e0c812cd..26c9d0d4 100644 --- a/docs/debugging +++ b/docs/debugging @@ -1,7 +1,7 @@ Debugging i3: How To ==================== Michael Stapelberg -February 2012 +December 2012 This document describes how to debug i3 suitably for sending us useful bug reports, even if you have no clue of C programming. @@ -21,25 +21,41 @@ i3 version 4.1.2-248-g51728ba (2012-02-12, branch "next") Your version can look like this: -4.1.2:: -You are using a release version. Please -upgrade to a development version first, or read -link:debugging-release-version.html[Debugging i3: How To (release version)]. +4.1.2 (release version):: +You are using a release version. In many cases, bugs are already +fixed in the development version of i3. If they aren’t, 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. -4.1.2-248-g51728ba:: +4.1.2-248-g51728ba (development version):: Your version is 248 commits newer than 4.1.2, and the git revision of your version is +51728ba+. Go to http://code.i3wm.org/i3/commit/?h=next and see if the line "commit" starts with the same revision. If so, you are using the latest version. -Development versions of i3 have several properties which make debugging easier: +Development versions of i3 have logging enabled by default and are compiled +with debug symbols. -1. Shared memory debug logging is enabled by default. You do not have to enable - logging explicitly. -2. Core dumps are enabled by default. -3. If you are using a version from the Debian/Ubuntu autobuilder, it is - compiled without optimization. Debug symbols are available in the i3-wm-dbg - package. When compiling i3 yourself, debug mode is the default. +== Enabling logging + +If you are using a development version (see previous section), you don’t 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, …), edit ++/usr/share/xsessions/i3.desktop+ and replace the +Exec=i3+ line with: + +------------------------------ +Exec=i3 --shmlog-size=26214400 +------------------------------ == Obtaining the debug logfile @@ -48,35 +64,39 @@ crashed, the logfile provides all information necessary to debug the problem. To save a compressed version of the logfile (suitable for attaching it to a bugreport), use: --------------------------------------------------------------------- -i3-dump-log | gzip -9c > /tmp/i3.log.gz --------------------------------------------------------------------- - -This command does not depend on i3 (it also works when i3 currently displays -the crash dialog), but it requires a working X11 connection. When running it -from a virtual console (Ctrl-Alt-F1), use: - -------------------------------------------------------------------- DISPLAY=:0 i3-dump-log | gzip -9c > /tmp/i3.log.gz -------------------------------------------------------------------- +This command does not depend on i3 (it also works while i3 displays +the crash dialog), but it requires a working X11 connection. + +== Compiling with debug symbols + +To actually get useful backtraces, you should make sure that your version of i3 +is compiled with debug symbols: + +------------------------------------------------------------------------------ +$ 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 +symbols (package +i3-wm-dbg+ on Debian for example) or if you can turn off +stripping. If nothing helps, please build i3 from source. + == Obtaining a backtrace -When i3 displays its crash dialog, do the following: +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. -1. Switch to a virtual console (Ctrl-Alt-F1) or login from a different computer -2. Generate a backtrace (see below) -3. Switch back to the crash dialog (Ctrl-Alt-F7) -4. Restart i3 in-place (you will keep your session), continue working - -This is how you get a backtrace from a running i3 process: - ------------------ -I3PID=$(pidof i3) -gdb /proc/$I3PID/exe $I3PID \ - --batch --quiet \ - --ex 'backtrace full' > /tmp/i3-backtrace.txt 2>&1 ------------------ +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 i3’s process +id (PID) and the second one is incremented each time you generate a backtrace, +starting at 0. == Sending bug reports/debugging on IRC