linux-kernel - [PATCH 3/3] can: mcan: m_can_class_unregister: fix order of unregistration calls

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Message-Id: <20250502-can-rx-offload-del-v1-3-59a9b131589d@pengutronix.de>
Date: Fri, 02 May 2025 16:13:46 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>, 
 Thomas Kopp <thomas.kopp@...rochip.com>, 
 Vincent Mailhol <mailhol.vincent@...adoo.fr>, kernel@...gutronix.de, 
 Heiko Stuebner <heiko@...ech.de>, 
 Chandrasekar Ramakrishnan <rcsekar@...sung.com>, 
 Markus Schneider-Pargmann <msp@...libre.com>
Cc: linux-can@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, 
 Marc Kleine-Budde <mkl@...gutronix.de>, stable@...r.kernel.org
Subject: [PATCH 3/3] can: mcan: m_can_class_unregister: fix order of
 unregistration calls

If a driver is removed, the driver framework invokes the driver's
remove callback. A CAN driver's remove function calls
unregister_candev(), which calls net_device_ops::ndo_stop further down
in the call stack for interfaces which are in the "up" state.

The removal of the module causes the a warning, as
can_rx_offload_del() deletes the NAPI, while it is still active,
because the interface is still up.

To fix the warning, first unregister the network interface, which
calls net_device_ops::ndo_stop, which disables the NAPI, and then call
can_rx_offload_del().

Fixes: 1be37d3b0414 ("can: m_can: fix periph RX path: use rx-offload to ensure skbs are sent from softirq context")
Cc: stable@...r.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
---
 drivers/net/can/m_can/m_can.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 884a6352c42b..7c430eaff5dd 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -2462,9 +2462,9 @@ EXPORT_SYMBOL_GPL(m_can_class_register);
 
 void m_can_class_unregister(struct m_can_classdev *cdev)
 {
+	unregister_candev(cdev->net);
 	if (cdev->is_peripheral)
 		can_rx_offload_del(&cdev->offload);
-	unregister_candev(cdev->net);
 }
 EXPORT_SYMBOL_GPL(m_can_class_unregister);
 

-- 
2.47.2