Re: [PATCH v3 2/3] genetlink: disallow subscribing to unknown mcast groups

[Johannes Berg <johannes@sipsolutions.net>]

On Wed, 2015-02-04 at 16:36 +0100, Bjørn Mork wrote:

> >> -	int i, err = 0;
> >> +	int i, err = -ENOENT;
> >>  
> >>  	down_read(&cb_lock);
> >>  	for (i = 0; i < GENL_FAM_TAB_SIZE; i++) {
> >
> > This change cause serious problems for acpid, as reported on
> > https://bugzilla.kernel.org/show_bug.cgi?id=92121
> 
> Ah, I see this bug is already fixed by commit 8b7c36d810c6 ("netlink:
> fix wrong subscription bitmask to group mapping in").  Your change was
> obviously correct, and found the long standing off by one bug.  Thanks.
> 
> Sorry about the noise.  I should have checked the current "net" first.

Interesting. I was completely willing to entertain the notion that some
userspace might be broken and be attempting to subscribe to a (static
through the hacks we had to put in or "I think I know it already")
group.

Have you checked acpid with the bitmap fix?

johannes