Sean Penn and Charlize Theron -- Cops Called Over Her Screaming Son

Sean Penn and Charlize Theron had their morning hike interrupted by cops Thursday ... after another hiker accused them of possibly mistreating Charlize's toddler ... but we're told cops determined they did nothing wrong ... TMZ has learned.

The incident went down at Vasquez Rocks in Santa Clarita, CA. Charlize and Sean were having a sunrise picnic when a female hiker with a camera stopped after she heard Charlize's 2-year-old son Jackson screaming in a tantrum. The hiker went towards the child and started filming.

We're told Charlize told the woman not to go near Jackson, so the hiker left and called the cops and claimed something bad might have happened to the kid.

We're told the deputies quickly determined nothing happened. Jackson was just on a timeout and got really upset. The deputies concluded the timeout involved no physical contact, so they left and no action will be taken.