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Re: options RND_COM considered dangeous

On Mon, Nov 17, 2008 at 07:48:09AM +1100, Daniel Carosone wrote:
> On Sat, Nov 15, 2008 at 04:10:34PM -0500, Rafal Boni wrote:
> > I just got a locking-against-myself panic on an XScale pxa250 (ARM)
> > [..]
> > 
> > It looks like the problem is that the callout data is protected by locks
> > at IPL_SCHED whereas com(4) interrupts at IPL_HIGH; the lock that is being
> > locked recursively is the callout lock.
> > 
> > I don't know if there are serial drivers that run at-or-below-IPL_SCHED,
> > but if not, it might make sense to remove the RND_COM option.
> It's been marked broken in i386 configs for exactly this reason;
> apparently the same applies elsewhere.  

I think it should be removed, or at a minimum its processing moved to the
soft interrupt.


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