Re: [PATCH net v2] net/sched: dualpi2: clear stale classification on filter miss

[Jamal Hadi Salim]

On Tue, Jun 9, 2026 at 7:26 PM Samuel Moelius
<sam.moelius@xxxxxxxxxxxxxxx> wrote:
>
> DualPI2 leaves previous classification state attached to an skb when
> filter classification returns no match.  The enqueue path can then act
> on stale state from an earlier classification attempt.
>
> A filter miss should fall back to the default path without reusing old
> per-packet classification data.
>
> Clear the classification result when the filter lookup does not match.
>

Why not just initialize at the top of the function? Something like this:

--- a/net/sched/sch_dualpi2.c
+++ b/net/sched/sch_dualpi2.c
@@ -346,6 +346,8 @@ static int dualpi2_skb_classify(struct
dualpi2_sched_data *q,
        struct tcf_proto *fl;
        int result;

+       cb->classified = DUALPI2_C_CLASSIC;

Then you can even remove check around if (!fl)

-       if (!fl) {
-               cb->classified = DUALPI2_C_CLASSIC;
+       if (!fl)
                return NET_XMIT_SUCCESS;
-       }

Would improve readability.

cheers,
jamal