Nikki Sixx's youngest son, Decker, is back home (sweet home) after a family argument sent him running to a friend's house -- and after Nikki called the cops to report the boy missing.

According to an exclusive TMZ report, the incident occurred last week, coming to a head when Sixx phoned police to say Decker had gone missing. However, it seems Sixx had a strong idea of where to find him.

TMZ's sources say Sixx knew exactly where his son was -- and after deputies tracked the boy down at a friend's house, they were able to settle the matter fairly quickly by letting him know his family was looking for him. As the TMZ report put it, "the kid decided to do just that."

All's well that ends well, right? This is just the type of thing that happens when rock legends are on a break from touring. Fortunately, Sixx will get back on the road with Motley Crue in December, heading to the UK for a package tour with Def Leppard and Steel Panther.