Explanation for the "nm-dispatcher: Caught signal 15, shutting down..." message

25 January 2025, 20:42:26

I'm writing this post just because I've been curious why this message appears in the first place and because I couldn't find any promising explanations on the web.

So, if you use OpenRC with NetworkManager then you've probably noticed this during shutdown:

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nm-dispatcher: req:2 'down' [wlan0], "/etc/NetworkManager/dispatcher.d/10-openrc-status": complete: proccess failed with Script '/etc/NetworkManager/dispatcher.d/10-openrc-status' exited with status 1
nm-dispatcher: Caught signal 15, shutting down...

The message has been around for 13 years, but there doesn't seem to be any solutions for it. So, after digging through docs and scripts for a few hours, I came to the following conclusion:

This message isn't the result of the NetworkManager service stopping, but rather dbus. After the NetworkManager service gets the stop command, the program itself exits, but then a new process appears called nm-dispatcher, which is used to execute scripts after NetworkManager shuts down (well, it can do more, but that's the behaviour in this situation). The important thing is that nm-dispatcher runs for about 5 seconds afterwards and depends on dbus (just like NetworkManager itself). If the dbus service also stops in this time frame, nm-dispatcher gets the signal to exit, which is what happens during shutdown and why this message is logged: it's technically an "error". But it's harmless since the system is already powering off.

AFAIK, there really isn't a way to "solve" this other than getting a service to stop between NetworkManager and dbus in order to give nm-dispatcher enough time to gracefully exit. Or just setting a lower log level.

Anyway, I hope this post helps someone who will be looking for this message in the future