sounds like it may have a short in it somewhere if it’s electric. Find the breaker or fuse for it and turn it off. If it is gas turn the gas valve off, it means no hot water until it’s fixed but at least you’ll sleep better.

Seriously, for what it is going to cost to have a repair man come out and fix it, buy yourself a new water heater and have them install it, or do it yerself!!!!!!

It does depend whether it’s an electric or gas heater.

Either way, you have a problem that will be solved by replacing it. Especially if it’s old.

Sooty smell is usually a vent problem.
You said smoke though which leans me to think it’s an electric heater with a thermostat problem.

you probably just need a new heating element 30-50 bucks
at home depot,it could also be your high temp pop off valve is discharging into the floor under or near the base of the water heater if it wet just call the plumber

When you have it checked if it does not need to be replaced have them empty the tank. It may need to be refurbished. If it isn’t working the heating coils more than likely are gone. Make sure you get a complete estimate before you allow it to be repaired it may be wiser and better in the long run to buy new.

sounds like the burners are having a problem exhausting the fumes. If you can smell it, you should be concerned.

time to buy a new one

it means it is time to buy a new one

The inside is probably rotted out, you will probably need to buy a new one.