Tsan detected the race condition on the server parameter. It is being declared non-atomic, but being unprotectedly read here,  and being written (under mutex) via 
IDLServerParameterWithStorage wrapping class. To get rid of the race condition consider declaring the parameter atomic in its idl spec.
Note: storage_wrapper class used inside  IDLServerParameterWithStorage to wrap server parameter access has a template specialization for atomic types that allows to avoid nested atomicity and prevent additional overhead.