Re: [PATCH] kernfs: skip lockdep annotation always if ignore_lockdep is set

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Fri, Feb 07, 2014 at 02:53:13PM -0500, Tejun Heo wrote:
> On Fri, Feb 07, 2014 at 09:47:01PM +0200, Imre Deak wrote:
> > We skip lockdep annotations for sysfs attributes with ignore_lockdep
> > set. An exception is kernfs_deactivate where we annotate even in this
> > case. Since the lockdep map key needed for the annotation is not
> > initialized whenever ignore_lockdep is set, we'll get a warning for
> > the uninitialized key.
> > 
> > Note that this happens since,
> > 
> > commit 517e64f57883bd63c5a4ab8b3d0d3ed68c55d0cf
> > Author: Tejun Heo <tj@kernel.org>
> > Date:   Thu Nov 28 14:54:29 2013 -0500
> > 
> > Before this change we had a valid key even in case of ignore_lockdep, so
> > the annotation in kernfs_deactivate worked, or at least didn't produce
> > the above warning. Fix this by skipping the annotation whenever
> > ignore_lockdep is set.
> > 
> > The actual attribute triggering the bug was 'delete_device' in
> > drivers/i2c/i2c-core.c, for the backtrace see the reference below.
> 
> I think Greg already has about the same patch queued.
> 
>   http://lkml.kernel.org/g/20140129170403.GJ30842@htj.dyndns.org

Yes, I just sent it to Linus a few minutes ago.

thanks,

greg k-h