How to View Core Dump Causes?
===============================

After a program crashes abnormally, how can I check the cause of the core dump?

-  Maintainer: \ daohu527@gmail.com
-  Version: 1.0.0
-  Date: 05/19/2024
-  Description:

Answer
------

After a program crashes abnormally, you can use the core dump file to check the specific error cause.

Core Dump File Path
~~~~~~~~~~~~~~~~~~~

Apollo's core dump files are stored in the ``data/core`` directory. When the program crashes, the system generates a core dump file, usually named `core` or `core.pid`, where `pid` is the process ID.

Checking the Cause of the Core Dump
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

``gdb`` (GNU Debugger) is a powerful tool for analyzing core dump files. You need to provide the executable that generated the core dump file and the core dump file itself. Here are the specific steps:

1. Start gdb and load the executable file and core dump file:

   .. code:: shell

      gdb <path-to-executable> <path-to-core-dump>

   For example:

   .. code:: shell

      gdb ./my_program data/core/core.12345

2. In gdb, view the stack information at the time of the crash:

   .. code:: shell

      (gdb) bt

   The ``bt`` (backtrace) command will display the call stack at the time of the crash, which helps in locating the issue.

Example
~~~~~~~

Suppose the generated core dump file is ``core.12345``, you can check it as follows:

.. code:: shell

   $ gdb mainboard data/core/core.12345

At the gdb prompt:

.. code:: shell

   (gdb) bt
   # This will show the call stack
   (gdb) info locals
   # Display the local variables in the current frame
   (gdb) print some_variable
   # Print the value of the variable some_variable
   (gdb) list
   # Show the current line of code being executed
   (gdb) list my_program.c:42
   # View the code at line 42 of my_program.c

By following these steps, you can deeply analyze the reason for the program crash and perform corresponding debugging and fixes.