The Free On-line Dictionary of Computing (30 December 2018):

problem state

   IBM jargon for user mode, the opposite of "supervisor
   state".

   On IBM System 360, 370 and 390 mainframes privileged
   instructions may only be executed in "supervisor state".
   Application programs request the operating system to
   perform these operations by using the Supervisor Call (SVC)
   instruction.

   (1995-02-15)