[PATCH] can: j1939: undo increment when j1939_local_ecu_get() fails

[PATCH] can: j1939: undo increment when j1939_local_ecu_get() fails

[Tetsuo Handa]

Since j1939_sk_bind() and j1939_sk_release() call j1939_local_ecu_put()
when J1939_SOCK_BOUND was already set, but the error handling path for
j1939_sk_bind() will not set J1939_SOCK_BOUND when j1939_local_ecu_get()
fails, j1939_local_ecu_get() needs to undo priv->ents[sa].nusers++ when
j1939_local_ecu_get() returns an error.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
---
 net/can/j1939/bus.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/can/j1939/bus.c b/net/can/j1939/bus.c
index 39844f14eed8..797719cb227e 100644
--- a/net/can/j1939/bus.c
+++ b/net/can/j1939/bus.c
@@ -290,8 +290,11 @@ int j1939_local_ecu_get(struct j1939_priv *priv, name_t name, u8 sa)
 	if (!ecu)
 		ecu = j1939_ecu_create_locked(priv, name);
 	err = PTR_ERR_OR_ZERO(ecu);
-	if (err)
+	if (err) {
+		if (j1939_address_is_unicast(sa))
+			priv->ents[sa].nusers--;
 		goto done;
+	}
 
 	ecu->nusers++;
 	/* TODO: do we care if ecu->addr != sa? */
-- 
2.51.0

Re: [PATCH] can: j1939: undo increment when j1939_local_ecu_get() fails

[Oleksij Rempel]

On Sun, Aug 24, 2025 at 07:27:40PM +0900, Tetsuo Handa wrote:
> Since j1939_sk_bind() and j1939_sk_release() call j1939_local_ecu_put()
> when J1939_SOCK_BOUND was already set, but the error handling path for
> j1939_sk_bind() will not set J1939_SOCK_BOUND when j1939_local_ecu_get()
> fails, j1939_local_ecu_get() needs to undo priv->ents[sa].nusers++ when
> j1939_local_ecu_get() returns an error.
> 
> Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>                                                                                                             
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>

Thank you!
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Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
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Re: [PATCH] can: j1939: undo increment when j1939_local_ecu_get() fails

[Tetsuo Handa]

On 2025/09/05 17:31, Oleksij Rempel wrote:
> On Sun, Aug 24, 2025 at 07:27:40PM +0900, Tetsuo Handa wrote:
>> Since j1939_sk_bind() and j1939_sk_release() call j1939_local_ecu_put()
>> when J1939_SOCK_BOUND was already set, but the error handling path for
>> j1939_sk_bind() will not set J1939_SOCK_BOUND when j1939_local_ecu_get()
>> fails, j1939_local_ecu_get() needs to undo priv->ents[sa].nusers++ when
>> j1939_local_ecu_get() returns an error.
>>
>> Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
>> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> 
> Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>                                                                                                             
> Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
> 
> Thank you!

Thank you for responding.
Do I need to take some action (e.g. sending to netdev@vger.kernel.org )
on these three patches?

Re: [PATCH] can: j1939: undo increment when j1939_local_ecu_get() fails

[Oleksij Rempel]

On Sun, Sep 07, 2025 at 04:42:33PM +0900, Tetsuo Handa wrote:
> On 2025/09/05 17:31, Oleksij Rempel wrote:
> > On Sun, Aug 24, 2025 at 07:27:40PM +0900, Tetsuo Handa wrote:
> >> Since j1939_sk_bind() and j1939_sk_release() call j1939_local_ecu_put()
> >> when J1939_SOCK_BOUND was already set, but the error handling path for
> >> j1939_sk_bind() will not set J1939_SOCK_BOUND when j1939_local_ecu_get()
> >> fails, j1939_local_ecu_get() needs to undo priv->ents[sa].nusers++ when
> >> j1939_local_ecu_get() returns an error.
> >>
> >> Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
> >> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> > 
> > Tested-by: Oleksij Rempel <o.rempel@pengutronix.de>                                                                                                             
> > Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
> > 
> > Thank you!
> 
> Thank you for responding.
> Do I need to take some action (e.g. sending to netdev@vger.kernel.org )
> on these three patches?

Nothing is needed for now. As soon as CAN maintainers will have time to
take look at it, the patches will be taken or changes may be requested.

Best Regards,
Oleksij
-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

Re: [PATCH] can: j1939: undo increment when j1939_local_ecu_get() fails

[Marc Kleine-Budde]

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On 24.08.2025 19:27:40, Tetsuo Handa wrote:
> Since j1939_sk_bind() and j1939_sk_release() call j1939_local_ecu_put()
> when J1939_SOCK_BOUND was already set, but the error handling path for
> j1939_sk_bind() will not set J1939_SOCK_BOUND when j1939_local_ecu_get()
> fails, j1939_local_ecu_get() needs to undo priv->ents[sa].nusers++ when
> j1939_local_ecu_get() returns an error.
> 
> Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Applied to linux-can.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde          |
Embedded Linux                   | https://www.pengutronix.de |
Vertretung Nürnberg              | Phone: +49-5121-206917-129 |
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