Re: [PATCH net-next,v4] bonding: return -ENOMEM instead of BUG in alb_upper_dev_walk

[Jay Vosburgh <jay.vosburgh@canonical.com>]

Zhengchao Shao <shaozhengchao@huawei.com> wrote:

>If failed to allocate "tags" or could not find the final upper device from
>start_dev's upper list in bond_verify_device_path(), only the loopback
>detection of the current upper device should be affected, and the system is
>no need to be panic.
>So return -ENOMEM in alb_upper_dev_walk to stop walking, print some warn
>information when failed to allocate memory for vlan tags in
>bond_verify_device_path.
>
>I also think that the following function calls
>netdev_walk_all_upper_dev_rcu
>---->>>alb_upper_dev_walk
>---------->>>bond_verify_device_path
>From this way, "end device" can eventually be obtained from "start device"
>in bond_verify_device_path, IS_ERR(tags) could be instead of
>IS_ERR_OR_NULL(tags) in alb_upper_dev_walk.
>
>Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>

Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>

>---
>v4: print information instead of warn
>v3: return -ENOMEM instead of zero to stop walk
>v2: use WARN_ON_ONCE instead of WARN_ON
>---
> drivers/net/bonding/bond_alb.c  | 3 ++-
> drivers/net/bonding/bond_main.c | 5 ++++-
> 2 files changed, 6 insertions(+), 2 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
>index dc2c7b979656..7edf0fd58c34 100644
>--- a/drivers/net/bonding/bond_alb.c
>+++ b/drivers/net/bonding/bond_alb.c
>@@ -985,7 +985,8 @@ static int alb_upper_dev_walk(struct net_device *upper,
> 	if (netif_is_macvlan(upper) && !strict_match) {
> 		tags = bond_verify_device_path(bond->dev, upper, 0);
> 		if (IS_ERR_OR_NULL(tags))
>-			BUG();
>+			return -ENOMEM;
>+
> 		alb_send_lp_vid(slave, upper->dev_addr,
> 				tags[0].vlan_proto, tags[0].vlan_id);
> 		kfree(tags);
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 51d47eda1c87..1a40bd08f984 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -2967,8 +2967,11 @@ struct bond_vlan_tag *bond_verify_device_path(struct net_device *start_dev,
> 
> 	if (start_dev == end_dev) {
> 		tags = kcalloc(level + 1, sizeof(*tags), GFP_ATOMIC);
>-		if (!tags)
>+		if (!tags) {
>+			net_err_ratelimited("%s: %s: Failed to allocate tags\n",
>+					    __func__, start_dev->name);
> 			return ERR_PTR(-ENOMEM);
>+		}
> 		tags[level].vlan_proto = BOND_VLAN_PROTO_NONE;
> 		return tags;
> 	}
>-- 
>2.34.1
>
>