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Subjectcopy to user
The reason that I need it to spend CPU time is that I'm developing a fault
injector. The purpose of a fault injection tool is, as you could imagine,
to test some critical systems and it's capacity to recover from fails. The
reason for changing the code of a process is that process must be delayed
but without leaving the CPU - everything must look like nothing wrong is
happening, except for other processes that are waiting for something from
the delayed process...

Maybe I should have explained this before... sorry.

I suppose now you can understand why SIGSTOP won't work. Hope you can help
me :)

About using udelay... this soluction seemed fine to me at first but if I
hang the CPU with udelay the scheduler will no be doing it's job (isn't
it?). This would give me even more intrusiveness (another requirement: the
less intrusiveness as possible).

Isn't there any doubt that copy_to_user can handle my problem? When I use
it to change CS, this function returns the correct number of bytes (and no
error) but, when I try to read... the old data is still there. I suppose
there is a page/segment protection against writing to CS, isn't it?

Luis Henriques

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