Re: orinoco driver causes *lots* of lockdep spew

From: Herbert Xu
Date: Thu Aug 03 2006 - 21:04:08 EST

On Thu, Aug 03, 2006 at 08:22:58AM -0700, Arjan van de Ven wrote:
> however I'm not quite yet convinced that this patch is going to solve
> this particular deadlock.
> (I agree with the principle of it and I think it's really needed,
> I just don't yet see how it's going to solve this specific deadlock. But
> then again it's early and I've not had sufficient coffee yet so I could
> well be wrong)

Well it solves the dead lock by breaking the chain that links the
netlink system with the jungle of wireless locking :)

The spin lock in sk_buff_head acts as a mediator. We only feed the
skb to the netlink system once that spin lock has been dropped.

> it's not just about irq context, it's about being called with any lock
> that's
> used in IRQ context; that is what makes this double nasty...

Yes it is nasty. However, so far wireless seems to be the only offender.

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Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
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