Jim Jones wasn’t happy about a fire drill at his recent show … roasting the venue for having to evacuate after someone smoked in the bathroom — and, it ended up ruining the whole evening.

The rapper was all set to perform at a venue in an upstate New York town … crowd packed in, mic in hand and ready to rap — when someone decided to light up in the bathroom and accidentally set off the fire alarm.

An eyewitness tells us ownership looked into the fire alarm … and, while it seems there was no imminent threat to safety, they still decided they needed everyone to evacuate before coming back in.

Jones was clearly upset too … pointing out people are already in their seats, very comfortable — and, it would be quicker just to get on with the show.

He even gets into a short tête-à-tête with the DJ in the building who is clearly trying to usher people out so they can get the show going, to no avail.

JJ mockingly calls the whole situation a “fire drill” … joking he hasn’t had one since elementary school before adding this whole moment’s gonna go viral — and people need to whip out their phones.

We’re told the performance didn’t go on … ’cause once people were forced to evacuate many decided to just bounce — really screwing up the whole night.