ceph/doc/dev/developer_guide/debugging-gdb.rst

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GDB - The GNU Project Debugger
==============================
`The GNU Project Debugger (GDB) <https://www.sourceware.org/gdb>`_ is
a powerful tool that allows you to analyze the execution flow
of a process.
GDB can help to find bugs, uncover crash errors or track the
source code during execution of a development cluster.
It can also be used to debug Teuthology test runs.
GET STARTED WITH GDB
--------------------
Basic usage with examples can be found `here. <https://geeksforgeeks.org/gdb-command-in-linux-with-examples>`_
GDB can be attached to a running process. For instance, after deploying a
development cluster, the process number (PID) of a ``ceph-osd`` daemon can be found in::
$ cd build
$ cat out/osd.0.pid
Attaching gdb to the process::
$ gdb ./bin/ceph-osd -p <pid>
.. note::
It is recommended to compile without any optimizations (``-O0`` gcc flag)
in order to avoid elimination of intermediate values.
Stopping for breakpoints while debugging may cause timeouts, so the following
configuration options are suggested::
[osd]
osd_op_thread_timeout = 1500
osd_op_thread_suicide_timeout = 1500
Debugging Teuthology Tests
^^^^^^^^^^^^^^^^^^^^^^^^^^
``src/script/ceph-debug-docker.sh`` can be used to analyze Teuthology failures::
$ ./ceph-debug-docker.sh <branch-name>
Refer to the script header for more information.