[apparmor] [PATCH 21/36] apparmor: baby step - now add labels to the labelset trees

[Seth Arnold]

On Wed, May 01, 2013 at 02:31:06PM -0700, John Johansen wrote:
> Just add the labels to the tree to make sure insertions and deletions
> into the rb tree are working.

> @@ -1330,6 +1347,8 @@ ssize_t aa_remove_profiles(char *fqname, size_t size)
>  		}
>  		name = profile->base.hname;
>  		__remove_profile(profile);
> +		aa_label_remove(&ns->labels, &profile->label);
> +		__aa_labelset_invalidate_all(ns, profile);
>  		mutex_unlock(&ns->lock);
>  	}

__remove_profile() may already call __aa_label_remove():

__remove_profile()
__list_remove_profile()
aa_put_profile()
aa_label_kref()
__aa_label_remove()

As a result of __remove_profile(), I believe that the next reference to
&profile->label may even be invalid:

...
aa_label_kref()
label_free_rcu()
aa_free_profile()
kzfree()


I guess the RCU mechanisms might mean that the data wouldn't actually
be reaped until after the above code has already run to completion --
I really should re-read the RCU paper -- but the mixing of cleanup
operations in current context vs in RCU callback is a bit more subtle
than me. :)

Thanks
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