[PATCH v5 net 0/6] net/sched: Fixes for sch_ingress and sch_clsact

[Peilin Ye <yepeilin.cs@gmail.com>]

Link to v4: https://lore.kernel.org/r/cover.1684825171.git.peilin.ye@bytedance.com/
Link to v3 (incomplete): https://lore.kernel.org/r/cover.1684821877.git.peilin.ye@bytedance.com/
Link to v2: https://lore.kernel.org/r/cover.1684796705.git.peilin.ye@bytedance.com/
Link to v1: https://lore.kernel.org/r/cover.1683326865.git.peilin.ye@bytedance.com/

Hi all,

These are v5 fixes for ingress and clsact Qdiscs.  Please take another
look at patch 1, 2 and 6, thanks!

Changes in v5:
  - for [6/6], reinitialize @q, @p (suggested by Vlad) and @tcm after the
    "replay:" tag
  - for [1,2/6], do nothing in ->destroy() if ->parent isn't ffff:fff1, as
    reported by Pedro

Change in v3, v4:
  - add in-body From: tags

Changes in v2:
  - for [1-5/6], include tags from Jamal and Pedro
  - for [6/6], as suggested by Vlad, replay the request if the current
    Qdisc has any ongoing (RTNL-unlocked) filter requests, instead of
    returning -EBUSY to the user
  - use Closes: tag as warned by checkpatch

[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()

[a] https://syzkaller.appspot.com/bug?extid=b53a9c0d1ea4ad62da8b

Thanks,
Peilin Ye (6):
  net/sched: sch_ingress: Only create under TC_H_INGRESS
  net/sched: sch_clsact: Only create under TC_H_CLSACT
  net/sched: Reserve TC_H_INGRESS (TC_H_CLSACT) for ingress (clsact)
    Qdiscs
  net/sched: Prohibit regrafting ingress or clsact Qdiscs
  net/sched: Refactor qdisc_graft() for ingress and clsact Qdiscs
  net/sched: qdisc_destroy() old ingress and clsact Qdiscs before
    grafting

 include/net/sch_generic.h |  8 +++++
 net/sched/sch_api.c       | 68 ++++++++++++++++++++++++++++-----------
 net/sched/sch_generic.c   | 14 ++++++--
 net/sched/sch_ingress.c   | 16 +++++++--
 4 files changed, 83 insertions(+), 23 deletions(-)

-- 
2.20.1