From ab92116c44de88697203f60d6a655da62eb211cc Mon Sep 17 00:00:00 2001
From: Justin M. Forbes <jforbes@redhat.com>
Date: Mar 22 2017 20:12:43 +0000
Subject: don't forget the patch


---

diff --git a/genetlink-fix-counting-regression-on-ctrl_dumpfamily.patch b/genetlink-fix-counting-regression-on-ctrl_dumpfamily.patch
new file mode 100644
index 0000000..ab048d1
--- /dev/null
+++ b/genetlink-fix-counting-regression-on-ctrl_dumpfamily.patch
@@ -0,0 +1,55 @@
+From: Stanislaw Gruszka <sgruszka@redhat.com>
+Date: 2017-03-22 15:08:33
+Subject: [PATCH 4.11] genetlink: fix counting regression on ctrl_dumpfamily()
+
+Commit 2ae0f17df1cd ("genetlink: use idr to track families") replaced
+
+	if (++n < fams_to_skip)
+		continue;
+into:
+
+	if (n++ < fams_to_skip)
+		continue;
+
+This subtle change cause that on retry ctrl_dumpfamily() call we omit
+one family that failed to do ctrl_fill_info() on previous call, because
+cb->args[0] = n number counts also family that failed to do
+ctrl_fill_info().
+
+Patch fixes the problem and avoid confusion in the future just decrease
+n counter when ctrl_fill_info() fail.
+
+User visible problem caused by this bug is failure to get access to
+some genetlink family i.e. nl80211. However problem is reproducible
+only if number of registered genetlink families is big enough to
+cause second call of ctrl_dumpfamily().
+
+Cc: Xose Vazquez Perez <xose.vazquez@gmail.com>
+Cc: Larry Finger <Larry.Finger@lwfinger.net>
+Cc: Johannes Berg <johannes@sipsolutions.net>
+Fixes: 2ae0f17df1cd ("genetlink: use idr to track families")
+Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
+---
+Dave, please also target this for 4.10+ -stable.
+
+ net/netlink/genetlink.c |    4 +++-
+ 1 files changed, 3 insertions(+), 1 deletions(-)
+
+diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
+index fb6e10f..92e0981 100644
+--- a/net/netlink/genetlink.c
++++ b/net/netlink/genetlink.c
+@@ -783,8 +783,10 @@ static int ctrl_dumpfamily(struct sk_buff *skb, struct netlink_callback *cb)
+ 
+ 		if (ctrl_fill_info(rt, NETLINK_CB(cb->skb).portid,
+ 				   cb->nlh->nlmsg_seq, NLM_F_MULTI,
+-				   skb, CTRL_CMD_NEWFAMILY) < 0)
++				   skb, CTRL_CMD_NEWFAMILY) < 0) {
++			n--;
+ 			break;
++		}
+ 	}
+ 
+ 	cb->args[0] = n;
+-- 
+1.7.1