> I failed to consider of modifying instructions in text segment.
>   ...
> pmap_procwr() is also called mips/mips/procfs_mem.c and I see software
> breakpointing is a trouble source.  I suspect the issue can be solved
> in other ways.

I think the I$-barrier operation has to be done in the target process
context when it resumes excution after the text space was changed by
others (it would imply full scale I$ invalidation).

Tohru Nishimura