Re: [patch 5/8] hrtimer remove state field

[Thomas Gleixner]

Roman,

> I have an idea what might have happened. You don't advance the pending 
> state, if the signal isn't queued, so that the pending state is screwed up 
> afterwards. Although I don't see how it could crash the kernel (it has 
> only the potential to mess up the timer queue via hrtimer_forward() a 
> bit), but I don't know what other patches were applied.

Good catch, but I dont see how it would trigger the bug.

> For example no current user restarts an active timer, which could be used 
> to simplify the locking.

How does this simplify the locking ? It just removes the
hrtimer_cancel() call in hrtimer_start() and makes the
switch_hrtimer_base() code a bit simpler. 

The general locking rules would be still the same and I dont see
increased flexibility at all.

> If we tightened a bit what a user is allowed to 
> do, we could gain flexibility on the other side, e.g. allow drivers to 
> create timer sources or how to integrate cpu timer.

-ENOPARSE. Can you please explain what "allow drivers to create timer
sources" means and why the above locking is in the way ?

	tglx


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