FAILED: patch "[PATCH] mlxsw: spectrum_router: Fix rollback in tunnel next hop init" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 665030fd0c1ed9f505932e6e73e7a2c788787a0a Mon Sep 17 00:00:00 2001
From: Petr Machata <[email protected]>
Date: Wed, 29 Jun 2022 10:02:05 +0300
Subject: [PATCH] mlxsw: spectrum_router: Fix rollback in tunnel next hop init

In mlxsw_sp_nexthop6_init(), a next hop is always added to the router linked list, and mlxsw_sp_nexthop_type_init() is invoked afterwards. When that function results in an error, the next hop will not have been removed from the linked list. As the error is propagated upwards and the caller frees the next hop object, the linked list ends up holding an invalid object.

A similar issue comes up with mlxsw_sp_nexthop4_init(), where rollback block does exist, however does not include the linked list removal.

Both IPv6 and IPv4 next hops have a similar issue with next-hop counter rollbacks. As these were introduced in the same patchset as the next hop linked list, include the cleanup in this patch.

index 9dbb573d53ea..0d8a0068e4ca 100644
@@ -4415,6 +4415,8 @@ static int mlxsw_sp_nexthop4_init(struct mlxsw_sp *mlxsw_sp,
 	return 0;
 
 err_nexthop_neigh_init:
+	list_del(&nh->router_list_node);
+	mlxsw_sp_nexthop_counter_free(mlxsw_sp, nh);
 	mlxsw_sp_nexthop_remove(mlxsw_sp, nh);
 	return err;
 }

@@ -6740,6 +6742,7 @@ static int mlxsw_sp_nexthop6_init(struct mlxsw_sp *mlxsw_sp,
 				  const struct fib6_info *rt)
 {
 	struct net_device *dev = rt->fib6_nh->fib_nh_dev;
+	int err;
 
 	nh->nhgi = nh_grp->nhgi;
 	nh->nh_weight = rt->fib6_nh->fib_nh_weight;

@@ -6755,7 +6758,16 @@ static int mlxsw_sp_nexthop6_init(struct mlxsw_sp *mlxsw_sp,
 		return 0;
 	nh->ifindex = dev->ifindex;
 
-	return mlxsw_sp_nexthop_type_init(mlxsw_sp, nh, dev);
+	err = mlxsw_sp_nexthop_type_init(mlxsw_sp, nh, dev);
+	if (err)
+		goto err_nexthop_type_init;
+
+	return 0;
+
+err_nexthop_type_init:
+	list_del(&nh->router_list_node);
+	mlxsw_sp_nexthop_counter_free(mlxsw_sp, nh);
+	return err;
 }
 
 static void mlxsw_sp_nexthop6_fini(struct mlxsw_sp *mlxsw_sp,