This is a note to let you know that I've just added the patch titled
can: dev: can_restart(): don't crash kernel if carrier is OK
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
can-dev-can_restart-don-t-crash-kernel-if-carrier-is.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f7ac17a9c29e0eb8634834c742b7a6558be5aeaa
Author: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Date: Thu Sep 28 21:58:23 2023 +0200
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@xxxxxxxxxxxxxx
Reviewed-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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.
