On Tue, May 23, 2023 at 12:12:39AM -0700, Peilin Ye wrote:

[1,2/6]: ingress and clsact Qdiscs should only be created under ffff:fff1
  [3/6]: Under ffff:fff1, only create ingress and clsact Qdiscs (for now,
         at least)
  [4/6]: After creating ingress and clsact Qdiscs under ffff:fff1, do not
         graft them again to anywhere else (e.g. as the inner Qdisc of a
         TBF Qdisc)
  [5/6]: Prepare for [6/6], do not reuse that for-loop in qdisc_graft()
         for ingress and clsact Qdiscs
  [6/6]: Fix use-after-free [a] in mini_qdisc_pair_swap()

In v5, I'll improve [6/6] according to Vlad's suggestion [a], and fix
[1,2/6] according to Pedro's report [b].

[a] https://lore.kernel.org/r/87sfbnxhg7.fsf@nvidia.com/ (local)
[b] https://lore.kernel.org/r/e462a91e-8bea-8b72-481c-4a36699e4149@mojatatu.com/ (local)

Thanks,
Peilin Ye