[B.A.T.M.A.N.] [PATCH] batman-adv: Deactive TO_BE_ACTIVATED hardif on shutdown

[B.A.T.M.A.N.] [PATCH] batman-adv: Deactive TO_BE_ACTIVATED hardif on shutdown

[Sven Eckelmann]

The shutdown of an batman-adv interface can happen with one of its slave
interfaces still being in the BATADV_IF_TO_BE_ACTIVATED state. A possible
reason for it is that the routing algorithm BATMAN_V was selected and
batadv_schedule_bat_ogm was not yet called for this interface. This slave
interface still has to be set to BATADV_IF_INACTIVE or the batman-adv
interface will never reduce its usage counter and thus never gets shutdown.

This problem can be simulated via:

    $ modprobe dummy
    $ modprobe batman-adv routing_algo=BATMAN_V
    $ ip link add bat0 type batadv
    $ ip link set dummy0 master bat0
    $ ip link set dummy0 up
    $ ip link del bat0
    unregister_netdevice: waiting for bat0 to become free. Usage count = 3

Fixes: 88861ea9acb7 ("[batman-adv] replacing if up/down timer with kernel notifications")
Reported-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
Please check https://www.open-mesh.org/issues/248 to learn more about the
bug

I have not checked why batadv_schedule_bat_ogm isn't called successfully
(which would mark the interface as active) in this situation.
---
 net/batman-adv/hard-interface.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 3240a67..f41b472 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -572,8 +572,7 @@ void batadv_hardif_disable_interface(struct batadv_hard_iface *hard_iface,
 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 	struct batadv_hard_iface *primary_if = NULL;
 
-	if (hard_iface->if_status == BATADV_IF_ACTIVE)
-		batadv_hardif_deactivate_interface(hard_iface);
+	batadv_hardif_deactivate_interface(hard_iface);
 
 	if (hard_iface->if_status != BATADV_IF_INACTIVE)
 		goto out;
-- 
2.8.0.rc3

Re: [B.A.T.M.A.N.] [PATCH] batman-adv: Deactive TO_BE_ACTIVATED hardif on shutdown

[Sven Eckelmann]

[-- Attachment #1: Type: text/plain, Size: 1379 bytes --]

On Saturday 19 March 2016 13:55:21 Sven Eckelmann wrote:
> The shutdown of an batman-adv interface can happen with one of its slave
> interfaces still being in the BATADV_IF_TO_BE_ACTIVATED state. A possible
> reason for it is that the routing algorithm BATMAN_V was selected and
> batadv_schedule_bat_ogm was not yet called for this interface. This slave
> interface still has to be set to BATADV_IF_INACTIVE or the batman-adv
> interface will never reduce its usage counter and thus never gets shutdown.
> 
> This problem can be simulated via:
> 
>     $ modprobe dummy
>     $ modprobe batman-adv routing_algo=BATMAN_V
>     $ ip link add bat0 type batadv
>     $ ip link set dummy0 master bat0
>     $ ip link set dummy0 up
>     $ ip link del bat0
>     unregister_netdevice: waiting for bat0 to become free. Usage count = 3
> 
> Fixes: 88861ea9acb7 ("[batman-adv] replacing if up/down timer with kernel
> notifications") Reported-by: Matthias Schiffer
> <mschiffer@universe-factory.net>
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> Please check https://www.open-mesh.org/issues/248 to learn more about the
> bug

I just want to emphasize that this patch doesn't fix the bug behind issue #248 
(only its main symptom described in the issue description). Please read the 
ticket and especially https://www.open-mesh.org/issues/248#note-4

Kind regards,
	Sven

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

Re: [B.A.T.M.A.N.] [PATCH] batman-adv: Deactive TO_BE_ACTIVATED hardif on shutdown

[Marek Lindner]

[-- Attachment #1: Type: text/plain, Size: 1093 bytes --]

On Saturday, March 19, 2016 13:55:21 Sven Eckelmann wrote:
> The shutdown of an batman-adv interface can happen with one of its slave
> interfaces still being in the BATADV_IF_TO_BE_ACTIVATED state. A possible
> reason for it is that the routing algorithm BATMAN_V was selected and
> batadv_schedule_bat_ogm was not yet called for this interface. This slave
> interface still has to be set to BATADV_IF_INACTIVE or the batman-adv
> interface will never reduce its usage counter and thus never gets shutdown.
> 
> This problem can be simulated via:
> 
>     $ modprobe dummy
>     $ modprobe batman-adv routing_algo=BATMAN_V
>     $ ip link add bat0 type batadv
>     $ ip link set dummy0 master bat0
>     $ ip link set dummy0 up
>     $ ip link del bat0
>     unregister_netdevice: waiting for bat0 to become free. Usage count = 3
> 
> Fixes: 88861ea9acb7 ("[batman-adv] replacing if up/down timer with kernel
> notifications") Reported-by: Matthias Schiffer
> <mschiffer@universe-factory.net>
> Signed-off-by: Sven Eckelmann <sven@narfation.org>

Applied in revision fbb98aa.

Thanks,
Marek

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 473 bytes --]