On FreeBSD and HardenedBSD, the message «no core dump - bad address» in your dmesg probably means that you have core dumps turned off.

Created by Lightning Bjornsson, Monday 07 April 2025

You may be here because you have asked a question like

I'm trying to debug this programme on FreeBSD or HardenedBSD, but it says in my logs «no core dump - bad address» (or something like that) and I don't get a core dump. What's wrong with my computer?

This is the frequently given answer to that question.

There's probably nothing wrong with your computer - your computer is probably not having trouble saving core dumps. Check the output of sysctl kern.coredump - if it says 0, you have core dumps disabled. (Ask your administrator to) change this value to 1 (for instance, by adding kern.coredump=1 to /etc/sysctl.conf, and then running sysctl -f /etc/sysctl.conf).

If it is already 1, and the message is «too large», check that you have enough free space in the volume on which the programme's working directory resides. Core dumps can be up to as large as the amount of virtual memory the programme can use.