LOTS of white exhaust should I be alarmed??

I have a Craftsman walk behind mower with Briggs and Straton engine and when I start it there is a constant stream of white smoke coming out the exhaust. I kinda' pay no mind I figure oil is cheap I'll let it burn off the bad stuff *cough cough* but it kind of aggravates me. I didn't do the whole yard just got to a good stopping place for now, looked at the filter and it's soaked in oil! I wiped it with a paper towel and the oil comes right off but... is this cuz I just kinda' put half the bottle of oil (abt 10oz of 10w30) in there without measuring it out? I'm sorry but measuring it out to be 'between those two lines' and KEEPING it 'between those two lines' is just more than tedious (when you can't see how large the basin is plus my eyes are bad in the first place making looking at the oil lvl pretty difficult)! Is there an easier way of maintaining your oil lvl? I'm kinda' new to lawn mowers and can due to learn from some expertise... or just good advise.

But again... about the white smoke, will it stop eventually or can I prevent it in the future? What's going on? will the CO2 police come pick me up if I do it too long? I had it worked on once when it did this to me last fall and it sort of stopped (still a puff of CO2 whenever I start it that I swear wasn't there before but... I took it to the only lawn mower repairman in town and if he says it's good and it's better I guess it's good...) but now it started again should I bring it back to him or find another though it might be 35 miles away :/ (I'd have to borrow a truck...)? I just lowered it so I guess it's working harder, but this is after just mowing it last week at the higher setting so shouldn't be bad.

Pull the dipstick and smell it. If it is overfull and smells like gas, time to change the oil and have the carb cleaning and rebuilt, with a new float needle and seat, part number 398188.

Think positive--your mosquito problem probably went away.

I've found the best way to add small amounts of oil to small engines is either by using a 30 to 50 cc syringe or a small Dawn dish soap bottle.

Yeah probably so cuz I've found that I probably just put too much oil in there. Gah just me bein lazy, thanks for the dawn dish suggestion that should come in use! My B&S mower is one of the newer ones where you don't change the oil... so I gotta figure out where that oil discharge lid is anyway lol I'd never changed the oil in anything in my life (don't own a car) so this should be interesting... where's that manual? And appreciate the part # too, yeah first time it happened I told the guy I was afraid it was a blown gasket... so yeah I know part numbers are important I don't know what else you said (now I'm soundin all hillbilly lol) but I will appreciate it xD off to give it another go, thanks for the advise!

Edit: @Rivets Oh I-C, yous seem to think it's a rider mower, no, it's a walk behind. After some research I'm ready to give it another go!

To change oil pull dipstick, have a small pan to collect oil, tip mower on it's side so oil will drain into pan. I would drain all oil out and start with 16 oz. of fresh oil.