How to debug Segmentation Faults (11) in Apache Error Logs?

Identifying the Cause of Segmentation Faults in Apache Error Logs

Apache error logs may sometimes report child processes exiting with the signal "Segmentation fault (11)". These segmentation faults are caused by memory access errors and can be difficult to debug.

To investigate the underlying cause of these faults within the Apache/PHP/MySQL stack using CakePHP, the following steps are recommended:

1. Attach gdb to a Child Process:

   Attach a debugging tool like gdb (GNU Debugger) to one of the running child processes of Apache. This will allow you to observe the crash and obtain a backtrace.

2. Run the Command:

   sudo gdb

   attach (e.g., attach 690 for PID 690)

3. Continue Execution and Wait for the Crash:

   c

4. Retrieve the Backtrace:

   backtrace or backtrace full.

This backtrace can provide valuable information about the memory access issue and the specific code that caused the crash.

5. Analyze the Backtrace:

   Examine the backtrace to identify the source of the Segmentation fault. It will typically indicate the file, line number, and function where the access violation occurred.

6. Reproduce the Issue:

   If the crash is intermittent, consider configuring Apache to run with a single child process using the following settings:

   StartServers 1
   MinSpareServers 1
   MaxSpareServers 1

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