Bulletin number:  386
Products affected: Dx205 Dx214
Description: Incorrect overlaying of configuration process
Component: icconf, occonf and icollect
Date: Thu Apr 2 11:57:46 BST 1992
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There is a potential problem when overlaying the configuration system
processes into the stack areas of a user processes.

The configurers do not take into account the fact that the 2 words
below the top of the stack (i.e. Wptr) are used to store scheduling
information of a de-scheduled process (or a process that has been
started using runp).

At present only 1 word is taken into account (i.e. the location Wptr -
1) which is used to store the Iptr of the process being started using
runp.  The second word (i.e. Wptr - 2) is NOT taken into account by
the configurers.

The problem will only arise if the code or data for a configuration
process is overlayed in the stack of a user process such that the top
of the code or data for the configuration process is at the location
Wptr - 2.

This can be fixed by not using the overlaying option of the
configurers by disabling it via a command line option.  It can also be
fixed by increasing the stack size of the user process (e.g. using
stacksize attribute) or by configuring with the G option (i.e.
configure for debugging).