From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Sat, 23 Nov 2013 13:01:50 +0100

net/netlink/genetlink.c: In function ‘genl_validate_assign_mc_groups’:
net/netlink/genetlink.c:217: warning: ‘err’ may be used uninitialized in this
function

Commit 2a94fe48f32ccf7321450a2cc07f2b724a444e5b ("genetlink: make multicast
groups const, prevent abuse") split genl_register_mc_group() in multiple
functions, but dropped the initialization of err.

Initialize err to zero to fix this.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
Question: Is the for_each_net_rcu() loop in genl_validate_assign_mc_groups()
          guaranteed to loop at least once?
	  If yes, this is a false positive.

Applied, but yes it's a false positive.  There is always &init_net so the
loop always iterates at least once.