mod_whatkilledus and mod_backtrace

Code on GitHub   

What are they for, briefly?

Log information which can help determine the cause of a web server child process crash and allow the circumstances of different crashes to be quickly compared in order to determine if the crashes need to be investigated individually.

What's new with version 2.01? (August 1, 2014)

mod_whatkilledus improvements

mod_backtrace improvements

Windows binaries

64-bit binaries are now included for use with httpd 2.2 and 2.4 on Windows. (32-bit binaries are still included.)

Refer to the Quick Start guide for information about a required software dependency.

Build improvements

Quick start


mod_whatkilledus v2.01 overview

mod_whatkilledus generates crash reports when a web server thread crashes. The crash reports include:

mod_whatkilledus documentation

mod_backtrace v2.01 overview

mod_backtrace can be used in two ways:

mod_backtrace documentation
Are you still using Apache httpd 2.0.x?

I'm not. I haven't tested the modules with 2.0.x, though I don't think there would be significant changes required.

Cost of use or distribution

This software is free — there is no cost to use or distribute this software either as-is or after modification to suit your purposes. At the same time, the author provides this software as-is, without any warranty. The license for this software is the Apache License, Version 2.0, and the license contains details about your rights and obligations as a user or distributor of this software. In particular, redistributors must comply with certain reasonable obligations described in the license.

Groups wishing to incorporate this software into their product for redistribution should not rely on my advice but instead should work with their legal counsel to make a final determination. In the event that specific questions need to be discussed with the author, use this contact information.


mod_whatkilledus currently contains a small bit of code from mod_log_forensic as well as the contents of test_char.h, both part of Apache HTTP Server.


Reports of problems or success or other inquiries about the software may be sent to the following e-mail address:

Jeff Trawick

Please include Diagnostic modules in the subject of your e-mail and provide the following information:

This is a free service, so I may not be able to reply individually; however, any information you are able to provide about problems will be used to improve this software in the future.

If you'd like to sponsor specific enhancements or resolution of specific problems, please let me know.

What was new with version 2.00? (September 2012)

Version 2.00 is a complete rewrite of earlier modules of the same names which provided similar functionality.

The original versions of the modules were written by me and donated to the Apache HTTP Server Project back in 2004, and committed to the Apache HTTP Server 1.3 source tree. Similar modules for Apache HTTP Server 2.x were not accepted into the 2.x tree but instead have been distributed from for many years. They have also been available from other commercial and non-commercial distributions.

Basic differences with mod_whatkilledus and mod_backtrace v2.00 from the original versions

In addition there are a number of implementation differences intended to improve various aspects of the software in less user-visible ways.