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.
With the mcp251xfd driver the removal of the module causes the following warning:
| WARNING: CPU: 0 PID: 352 at net/core/dev.c:7342 __netif_napi_del_locked+0xc8/0xd8
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().
All other driver using the rx-offload helper have been checked and the same issue has been found in the rockchip and m_can driver. These have been fixed, but only compile time tested. On the mcp251xfd the fix was tested on hardware.
Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- Marc Kleine-Budde (3): can: mcp251xfd: mcp251xfd_remove(): fix order of unregistration calls can: rockchip_canfd: m_can_class_unregister: fix order of unregistration calls can: mcan: m_can_class_unregister: fix order of unregistration calls
drivers/net/can/m_can/m_can.c | 2 +- drivers/net/can/rockchip/rockchip_canfd-core.c | 2 +- drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) --- base-commit: ebd297a2affadb6f6f4d2e5d975c1eda18ac762d change-id: 20250502-can-rx-offload-del-eb79379733dd
Best regards,
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.
With the mcp251xfd driver the removal of the module causes the following warning:
| WARNING: CPU: 0 PID: 352 at net/core/dev.c:7342 __netif_napi_del_locked+0xc8/0xd8
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: 55e5b97f003e ("can: mcp25xxfd: add driver for Microchip MCP25xxFD SPI CAN") Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c index 3bc56517fe7a..dd0b3fb42f1b 100644 --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c @@ -2174,8 +2174,8 @@ static void mcp251xfd_remove(struct spi_device *spi) struct mcp251xfd_priv *priv = spi_get_drvdata(spi); struct net_device *ndev = priv->ndev;
- can_rx_offload_del(&priv->offload); mcp251xfd_unregister(priv); + can_rx_offload_del(&priv->offload); spi->max_speed_hz = priv->spi_max_speed_hz_orig; free_candev(ndev); }
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: ff60bfbaf67f ("can: rockchip_canfd: add driver for Rockchip CAN-FD controller") Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- drivers/net/can/rockchip/rockchip_canfd-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c index 7107a37da36c..c3fb3176ce42 100644 --- a/drivers/net/can/rockchip/rockchip_canfd-core.c +++ b/drivers/net/can/rockchip/rockchip_canfd-core.c @@ -937,8 +937,8 @@ static void rkcanfd_remove(struct platform_device *pdev) struct rkcanfd_priv *priv = platform_get_drvdata(pdev); struct net_device *ndev = priv->ndev;
- can_rx_offload_del(&priv->offload); rkcanfd_unregister(priv); + can_rx_offload_del(&priv->offload); free_candev(ndev); }
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
^^^ Minor typo here.
Otherwise this looks good to me.
Reviewed-by: Markus Schneider-Pargmann
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: ff60bfbaf67f ("can: rockchip_canfd: add driver for Rockchip CAN-FD controller") Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de
drivers/net/can/rockchip/rockchip_canfd-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c index 7107a37da36c..c3fb3176ce42 100644 --- a/drivers/net/can/rockchip/rockchip_canfd-core.c +++ b/drivers/net/can/rockchip/rockchip_canfd-core.c @@ -937,8 +937,8 @@ static void rkcanfd_remove(struct platform_device *pdev) struct rkcanfd_priv *priv = platform_get_drvdata(pdev); struct net_device *ndev = priv->ndev;
- can_rx_offload_del(&priv->offload); rkcanfd_unregister(priv);
- can_rx_offload_del(&priv->offload); free_candev(ndev);
}
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@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.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);
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@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de
Reviewed-by: Markus Schneider-Pargmann msp@baylibre.com
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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