CMS has been seeing a periodic crash involving TH2::DoProjection while another thread happens to be doing a minimization. The incidents can be seen here
The problem is the following:
TH2::DoProjection calls TROOT::FindObject
TROOT::FindObject reads fSpecials without taking the lock
while TMinuit manipulates the list of specials while holding a lock. E.g.
If TH2::DoProjection is running concurrently as TMinuit is begin used, it leads to a data race which causes the crash.