Re: [rfc] [patch] kernel hooks

[Alan Cox]

On Thu, 2002-10-03 at 14:32, Richard J Moore wrote:
> 
> > You must also ensure that the code you are modifying isnt on an IRQ path
> > (if it is you must do spin locks and then be very careful about cross
> > cpu tlb deadlocks). Finally you have no choice but to ensure you never
> > use it on the NMI path
> 
> Why do we need a spinlock? We change one byte, we are not concered about
> when exactly that takes effect, only that there are always valid
> instructions in the pipeline.

Because you are programming for real silicon not for the imaginary
perfect processor. Read the x86 errata