****************** Debugging Asterisk ****************** Precondition ============ To debug asterisk crashes or freezes, you need the following debug packages on your Wazo: +----------------+---------------------------------------------------------------+---------------------------------------------------------------+---------------------------------------------------------------+ |General rule |XiVO < 14.18 |XiVO >= 14.18 |Wazo >= 16.16 | | | | | | +================+===============================================================+===============================================================+===============================================================+ |Example version |14.12 |14.18 |17.15 | +----------------+---------------------------------------------------------------+---------------------------------------------------------------+---------------------------------------------------------------+ |Commands |:: |:: |:: | | | | | | | | apt-get install xivo-fai-14.12 | xivo-dist xivo-14.18 | xivo-dist wazo-17.15 | | | apt-get update | apt-get update | apt-get update | | | apt-get install gdb | apt-get install gdb | apt-get install gdb libc6-dbg | | | apt-get install -t xivo-14.12 asterisk-dbg xivo-libsccp-dbg | apt-get install -t xivo-14.18 asterisk-dbg xivo-libsccp-dbg | apt-get install -t wazo-17.15 asterisk-dbg xivo-libsccp-dbg | | | | xivo-dist xivo-five | xivo-dist phoenix | | | | | | +----------------+---------------------------------------------------------------+---------------------------------------------------------------+---------------------------------------------------------------+ So There is a Problem with Asterisk. Now What ? =============================================== #. Find out the time of the incident from the people most likely to know #. Determine if there was a segfault #. The command ``grep segfault /var/log/syslog`` should return a line such as the following:: Oct 16 16:12:43 xivo-1 kernel: [10295061.047120] asterisk[1255]: segfault at e ip b751aa6b sp b5ef14d4 error 4 in libc-2.11.3.so[b74ad000+140000] #. Note the exact time of the incident from the segfault line. #. Follow the `Debugging Asterisk Crash`_ procedure. #. If you observe some of the following common symptoms, follow the `Debugging Asterisk Freeze`_ procedure. * The output of command ``service asterisk status`` says Asterisk PBX is running. * No more calls are distributed and phones go to ``No Service``. * Command ``core show channels`` returns only headers (no data) right before returning #. Fetch Asterisk logs for the day of the crash (make sure file was not already logrotated):: cp -a /var/log/asterisk/full /var/local/`date +"%Y%m%d"`-`hostname`-asterisk-full.log #. Fetch xivo-ctid logs for the day of the crash (make sure file was not already logrotated):: cp -a /var/log/xivo-ctid.log /var/local/`date +"%Y%m%d"`-`hostname`-xivo-ctid.log #. Open a new issue on the `bugtracker `_ with following information * Tracker: Bug * Status: New * Category: Asterisk * In versions: The version of your Wazo installation where the crash/freeze happened * Subject : ``Asterisk Crash`` or ``Asterisk Freeze`` * Description : Add as much context as possible, if possible, a scenario that lead to the issue, the date and time of issue, where we can fetch logs and backtrace * Attach logs and backtrace (if available) to the ticket (issue must be saved, then edited and files attached to a comment). Debugging Asterisk Crash ======================== When asterisk crashes, it usually leaves a core file in :file:`/var/spool/asterisk/`. You can create a backtrace from a core file named ``core_file`` with:: gdb -batch -ex "bt full" -ex "thread apply all bt" asterisk core_file > bt-threads.txt Debugging Asterisk Freeze ========================= You can create a backtrace of a running asterisk process with:: gdb -batch -ex "thread apply all bt" asterisk $(pidof asterisk) > bt-threads.txt If your version of asterisk has been compiled with the DEBUG_THREADS flag, you can get more information about locks with:: asterisk -rx "core show locks" > core-show-locks.txt .. note:: Debugging freeze without this information is usually a lot more difficult. Optionally, other information that can be interesting: * the output of ``asterisk -rx 'core show channels'`` * the verbose log of asterisk just before the freeze Recompiling Asterisk ==================== It's relatively straightforward to recompile the asterisk version of your Wazo with the DEBUG_THREADS and DONT_OPTIMIZE flag, which make debugging an asterisk problem easier. The steps are: #. Uncomment the ``deb-src`` line for the Wazo sources:: sed -i 's/^# *deb-src/deb-src/' /etc/apt/sources.list.d/xivo* #. Fetch the asterisk source package:: mkdir -p ~/ast-rebuild cd ~/ast-rebuild apt-get update apt-get install -y build-essential apt-get source asterisk #. Install the build dependencies:: apt-get build-dep -y asterisk #. Enable the DEBUG_THREADS and DONT_OPTIMIZE flag:: cd vim debian/rules #. Update the changelog by appending ``+debug1`` in the package version:: vim debian/changelog #. Rebuild the asterisk binary packages:: dpkg-buildpackage -us -uc This will create a couple of .deb files in the parent directory, which you can install via dpkg. Recompiling a vanilla version of Asterisk ----------------------------------------- It is sometimes useful to produce a "vanilla" version of Asterisk, i.e. a version of Asterisk that has none of the Wazo patches applied, to make sure that the problem is present in the original upstream code. This is also sometimes necessary before opening a ticket on the `Asterisk issue tracker `_. The procedure is similar to the one described above. Before calling ``dpkg-buildpackage``, you just need to: #. Make sure ``quilt`` is installed:: apt-get install -y quilt #. Unapply all the currently applied patches:: quilt pop -a #. Remove all the lines in the ``debian/patches/series`` file:: truncate -s0 debian/patches/series When installing a vanilla version of Asterisk on a XiVO 16.08 or earlier, you'll need to stop monit, otherwise it will restart asterisk every few minutes. Running Asterisk under Valgrind =============================== #. Install valgrind:: apt-get install valgrind #. Recompile asterisk with the DONT_OPTIMIZE flag. #. Edit :file:`/etc/asterisk/modules.conf` so that asterisk doesn't load unnecessary modules. This step is optional. It makes asterisk start (noticeably) faster and often makes the output of valgrind easier to analyze, since there's less noise. #. Edit :file:`/etc/asterisk/asterisk.conf` and comment the ``highpriority`` option. This step is optional. #. Stop monit and asterisk:: monit quit service asterisk stop #. Stop all unneeded Wazo services. For example, it can be useful to stop xivo-ctid, so that it won't interact with asterisk via the AMI. #. Copy the valgrind.supp file into /tmp. The valgrind.supp file is located in the contrib directory of the asterisk source code. #. Execute valgrind in the /tmp directory:: cd /tmp valgrind --leak-check=full --log-file=valgrind.txt --suppressions=valgrind.supp --vgdb=no asterisk -G asterisk -U asterisk -fnc Note that when you terminate asterisk with Control-C, asterisk does not unload the modules before exiting. What this means is that you might have lots of "possibly lost" memory errors due to that. If you already know which modules is responsible for the memory leak/bug, you should explicitly unload it before terminating asterisk. Running asterisk under valgrind takes a lots of extra memory, so make sure you have enough RAM. External links ============== * https://wiki.asterisk.org/wiki/display/AST/Debugging * http://blog.wazo.community/visualizing-asterisk-deadlocks.html * https://wiki.asterisk.org/wiki/display/AST/Valgrind