Subject: Re: [PATCH] of: Fix locking vs. interrupts

From: Benjamin Herrenschmidt <[email-masked]>
Date: Wed, 12 Jun 2013 18:56:27 +1000

On Wed, 2013-06-12 at 10:25 +0200, Thomas Gleixner wrote:
> On Wed, 12 Jun 2013, Benjamin Herrenschmidt wrote:
> 
> > The OF code uses irqsafe locks everywhere except in a handful of functions
> > for no obvious reasons. Since the conversion from the old rwlocks, this
> > now triggers lockdep warnings when used at interrupt time. At least one
> > driver (ibmvscsi) seems to be doing that from softirq context.
> > 
> > This converts the few non-irqsafe locks into irqsafe ones, making them
> > consistent with the rest of the code.
> 
> Fun. https://lkml.org/lkml/2013/2/4/416 seems to have got lost 
>  
> > Signed-off-by: Benjamin Herrenschmidt <[email-masked]>
> > CC: <[email-masked]> [v3.9+]
> 
> Acked-by: Thomas Gleixner <[email-masked]>
> 
> > ---
> > 
> > Note: It's silly to access the device-tree at interrupt time in most cases,
> > and we should probably fix ibmvscsi, but for the time being, let's fix the
> 
> Right.
> 
> > obvious bug. Thomas, this can probably still go into 3.10... If not, I've
> > CCed stable.
> 
> Should go through Grant I think.

Right, thinko. Sent to you due to the bug being exposed by your
conversion to spinlocks. Anyway, Grant got it now.

Cheers,
Ben.