There haven been reports, that the flexcan_close() soradically hangs during simultanious ifdown, sending of CAN messages and probably open CAN bus: | (__schedule) from [<808bbd34>] (schedule+0x90/0xb8) | (schedule) from [<808bf274>] (schedule_timeout+0x1f8/0x24c) | (schedule_timeout) from [<8016be44>] (msleep+0x18/0x1c) | (msleep) from [<80746a64>] (napi_disable+0x60/0x70) | (napi_disable) from [<8052fdd0>] (flexcan_close+0x2c/0x140) | (flexcan_close) from [<80744930>] (__dev_close_many+0xb8/0xd8) | (__dev_close_many) from [<8074db9c>] (__dev_change_flags+0xd0/0x1a0) | (__dev_change_flags) from [<8074dc84>] (dev_change_flags+0x18/0x48) | (dev_change_flags) from [<80760c24>] (do_setlink+0x44c/0x7b4) | (do_setlink) from [<80761560>] (rtnl_newlink+0x374/0x68c) I was unable to reproduce the issue, but a cleanup of the flexcan close sequence has probably fixed the problem at the reporting user. This patch changes the sequence in flexcan_close() to: - stop the TX queue - disable the interrupts on the chip level and wait via free_irq() synchronously for the interrupt handler to finish - disable RX offload, which disables synchronously NAPI - disable the flexcan on the chip level - free RX offload - disable the transceiver - close the CAN device - disable the clocks Link: https://lore.kernel.org/r/20201119085251.2949181-6-mkl@xxxxxxxxxxxxxx Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> --- drivers/net/can/flexcan.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 0fb768dee99f..60808d048ef6 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -1789,15 +1789,15 @@ static int flexcan_close(struct net_device *dev) struct flexcan_priv *priv = netdev_priv(dev); netif_stop_queue(dev); + flexcan_chip_interrupts_disable(dev); + free_irq(dev->irq, dev); can_rx_offload_disable(&priv->offload); flexcan_chip_stop_disable_on_error(dev); - flexcan_chip_interrupts_disable(dev); can_rx_offload_del(&priv->offload); - free_irq(dev->irq, dev); flexcan_transceiver_disable(priv); - close_candev(dev); + pm_runtime_put(priv->dev); can_led_event(dev, CAN_LED_EVENT_STOP); -- 2.29.2
