From: Menglong Dong <redacted>
Date: Sun, 1 Sep 2024 21:02:17 +0800

On Fri, Aug 30, 2024 at 11:04 PM Alexander Lobakin
[off-list ref] wrote:

[...]

quoted

quoted

@@ -1814,8 +1830,9 @@ static int vxlan_rcv(struct sock *sk, struct sk_buff *skb)
      return 0;

 drop:
+     reason = reason ?: SKB_DROP_REASON_NOT_SPECIFIED;

Is this possible that @reason will be 0 (NOT_DROPPED_YET) here? At the
beginning of the function, it's not initialized, then each error path
sets it to a specific value. In most paths, you check for it being != 0
as a sign of error, so I doubt it can be 0 here.

It can be 0 here, as we don't set a reason for every "goto drop"
path. For example, in the line:

    if (!vs)
        goto drop;

we don't set a reason, and the "reason" is 0 when we "goto drop",
as I don't think that it is worth introducing a reason here.

Aaah okay, I didn't notice that, thanks for the explanation!

Thanks!
Menglong Dong

quoted

quoted

      /* Consume bad packet */
-     kfree_skb(skb);
+     kfree_skb_reason(skb, reason);
      return 0;
 }

Thanks,
Olek