Re: [PATCH 3/3] can: mcan: m_can_class_unregister: fix order of unregistration calls

[Markus Schneider-Pargmann]

On Fri May 2, 2025 at 4:13 PM CEST, Marc Kleine-Budde wrote:
> 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@xxxxxxxxxxxxxxx
> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>

Reviewed-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>

> ---
>  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);
>

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