5.4-stable review patch. If anyone has any objections, please let me know.
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From: Marc Kleine-Budde mkl@pengutronix.de
[ 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-v2-1-91b5c1fd92... Reviewed-by: Vincent Mailhol mailhol.vincent@wanadoo.fr Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/can/dev/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c index 322da89cb9c60..b0f3bbc1d354f 100644 --- a/drivers/net/can/dev/dev.c +++ b/drivers/net/can/dev/dev.c @@ -552,7 +552,8 @@ 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.