From: Marc Kleine-Budde Date: Thu, 28 Sep 2023 19:58:23 +0000 (+0200) Subject: can: dev: can_restart(): don't crash kernel if carrier is OK X-Git-Tag: v6.6.7~1514 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b10de7204b2c574e9c6de0b37f3836b1c8a52884;p=platform%2Fkernel%2Flinux-starfive.git can: dev: can_restart(): don't crash kernel if carrier is OK [ Upstream commit fe5c9940dfd8ba0c73672dddb30acd1b7a11d4c7 ] During testing, I triggered a can_restart() with the netif carrier being OK [1]. The BUG_ON, which checks if the carrier is OK, results in a fatal kernel crash. This is neither helpful for debugging nor for a production system. [1] The root cause is a race condition in can_restart() which will be fixed in the next patch. Do not crash the kernel, issue an error message instead, and continue restarting the CAN device anyway. Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface") Link: https://lore.kernel.org/all/20231005-can-dev-fix-can-restart-v2-1-91b5c1fd922c@pengutronix.de Reviewed-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c index 7f9334a..a5bbdfa 100644 --- a/drivers/net/can/dev/dev.c +++ b/drivers/net/can/dev/dev.c @@ -132,7 +132,8 @@ static void can_restart(struct net_device *dev) struct can_frame *cf; int err; - BUG_ON(netif_carrier_ok(dev)); + if (netif_carrier_ok(dev)) + netdev_err(dev, "Attempt to restart for bus-off recovery, but carrier is OK?\n"); /* No synchronization needed because the device is bus-off and * no messages can come in or go out.