Patch "net: neigh: Fix netevent NETEVENT_DELAY_PROBE_TIME_UPDATE notification" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

net: neigh: Fix netevent NETEVENT_DELAY_PROBE_TIME_UPDATE notification

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-neigh-fix-netevent-netevent_delay_probe_time_update-notification.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Marcus Huewe <[email protected]>
Date: Wed, 15 Feb 2017 01:00:36 +0100
Subject: net: neigh: Fix netevent NETEVENT_DELAY_PROBE_TIME_UPDATE notification

From: Marcus Huewe <[email protected]>

[ Upstream commit 7627ae6030f56a9a91a5b3867b21f35d79c16e64 ]

When setting a neigh related sysctl parameter, we always send a NETEVENT_DELAY_PROBE_TIME_UPDATE netevent. For instance, when executing

	sysctl net.ipv6.neigh.wlp3s0.retrans_time_ms=2000

a NETEVENT_DELAY_PROBE_TIME_UPDATE netevent is generated.

This is caused by commit 2a4501ae18b5 ("neigh: Send a notification when DELAY_PROBE_TIME changes"). According to the commit's description, it was intended to generate such an event when setting the "delay_first_probe_time" sysctl parameter.

In order to fix this, only generate this event when actually setting the "delay_first_probe_time" sysctl parameter. This fix should not have any unintended side-effects, because all but one registered netevent callbacks check for other netevent event types (the registered callbacks were obtained by grepping for "register_netevent_notifier"). The only callback that uses the NETEVENT_DELAY_PROBE_TIME_UPDATE event is mlxsw_sp_router_netevent_event() (in drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c): in case of this event, it only accesses the DELAY_PROBE_TIME of the passed neigh_parms.

---
 net/core/neighbour.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -2927,7 +2927,8 @@ static void neigh_proc_update(struct ctl
 		return;
 
 	set_bit(index, p->data_state);
-	call_netevent_notifiers(NETEVENT_DELAY_PROBE_TIME_UPDATE, p);
+	if (index == NEIGH_VAR_DELAY_PROBE_TIME)
+		call_netevent_notifiers(NETEVENT_DELAY_PROBE_TIME_UPDATE, p);
 	if (!dev) /* NULL dev means this is default value */
 		neigh_copy_dflt_parms(net, p, index);
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/net-neigh-fix-netevent-netevent_delay_probe_time_update-notification.patch