We have become aware of a serious issue related to recent HP OpenVMS patch kits which can cause processes running RapidGen programs to appear to hang and/or enter a CPU bound loop. This behaviour only affects programs which CALL *SPAWN DCL commands and occurs after the command is executed and when the spawned process is terminating.
This problem is reportedly corrected by subsequently issued HP OpenVMS patch kits.
HP also describe the following effect of the bug in the DCL code which may affect non RapidGen processes:-
If a Telnet or Xwindows session on OpenVMS is terminated by closing the window (on a remote PC for example), it can cause a process on the OpenVMS system to go into a compute-bound loop using nearly 100% of the CPU. Typically this is seen when a subprocess is spawned in the session window, and then the session is terminated by clicking the window shut.
This problem has been seen on OpenVMS Alpha V8.3, with the DCL image delivered in the following patch kits:-
VMS83A_RMS-V0600
VMS83A_RMS-V0700
VMS83A_DCL-V0200
Solution
The looping process can normally be stopped via STOP/ID from a suitably privileged process.
The problem can be avoided by not applying any of the listed patches.
You are recommended to contact HP for details of remedial patch kits if you are affected by this issue.