netdev - Re: [PATCH] can: j1939: deactivate session upon receiving the second rts

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Message-ID: <aWdvd5lewInHv4TF@pengutronix.de>
Date: Wed, 14 Jan 2026 11:27:03 +0100
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Marc Kleine-Budde <mkl@...gutronix.de>
Cc: Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>,
	Robin van der Gracht <robin@...tonic.nl>, kernel@...gutronix.de,
	Oliver Hartkopp <socketcan@...tkopp.net>, linux-can@...r.kernel.org,
	Network Development <netdev@...r.kernel.org>
Subject: Re: [PATCH] can: j1939: deactivate session upon receiving the second
 rts

On Wed, Jan 14, 2026 at 11:22:34AM +0100, Marc Kleine-Budde wrote:
> On 14.01.2026 00:28:47, Tetsuo Handa wrote:
> > Since j1939_session_deactivate_activate_next() in j1939_tp_rxtimer() is
> > called only when the timer is enabled, we need to call
> > j1939_session_deactivate_activate_next() if we cancelled the timer.
> > Otherwise, refcount for j1939_session leaks, which will later appear as
> >
> >   unregister_netdevice: waiting for vcan0 to become free. Usage count = 2.
> >
> > problem.
> >
> > Reported-by: syzbot <syzbot+881d65229ca4f9ae8c84@...kaller.appspotmail.com>
> > Closes: https://syzkaller.appspot.com/bug?extid=881d65229ca4f9ae8c84
> > Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
> 
> Can you provide a Fixes tag? No need to resend. I'll add it while
> applying.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")

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