[Patch net 00/13] net_sched: close the race between call_rcu() and cleanup_net()

[Cong Wang <xiyou.wangcong@gmail.com>]

This patchset tries to fix the race between call_rcu() and
cleanup_net() again. Without holding the netns refcnt the
tc_action_net_exit() in netns workqueue could be called before 
filter destroy works in tc filter workqueue. This patchset
moves the netns refcnt from tc actions to tcf_exts, without
breaking per-netns tc actions.

Patch 1 reverts the previous fix, patch 2 introduces two new
API's to help to address the bug and the rest patches switch
to the new API's. Please see each patch for details.

I was not able to reproduce this bug, but now after adding
some delay in filter destroy work I manage to trigger the
crash. After this patchset, the crash is not reproducible
any more and the debugging printk's show the order is expected
too.

Fixes: ddf97ccdd7cb ("net_sched: add network namespace support for tc actions")
Reported-by: Lucas Bates <lucasb@mojatatu.com>
Cc: Lucas Bates <lucasb@mojatatu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

Cong Wang (13):
  Revert "net_sched: hold netns refcnt for each action"
  net_sched: introduce tcf_exts_get_net() and tcf_exts_put_net()
  cls_basic: use tcf_exts_get_net() before call_rcu()
  cls_bpf: use tcf_exts_get_net() before call_rcu()
  cls_cgroup: use tcf_exts_get_net() before call_rcu()
  cls_flow: use tcf_exts_get_net() before call_rcu()
  cls_flower: use tcf_exts_get_net() before call_rcu()
  cls_fw: use tcf_exts_get_net() before call_rcu()
  cls_matchall: use tcf_exts_get_net() before call_rcu()
  cls_route: use tcf_exts_get_net() before call_rcu()
  cls_rsvp: use tcf_exts_get_net() before call_rcu()
  cls_tcindex: use tcf_exts_get_net() before call_rcu()
  cls_u32: use tcf_exts_get_net() before call_rcu()

 include/net/act_api.h      |  4 +---
 include/net/pkt_cls.h      | 24 ++++++++++++++++++++++++
 net/sched/act_api.c        |  2 --
 net/sched/act_bpf.c        |  2 +-
 net/sched/act_connmark.c   |  2 +-
 net/sched/act_csum.c       |  2 +-
 net/sched/act_gact.c       |  2 +-
 net/sched/act_ife.c        |  2 +-
 net/sched/act_ipt.c        |  4 ++--
 net/sched/act_mirred.c     |  2 +-
 net/sched/act_nat.c        |  2 +-
 net/sched/act_pedit.c      |  2 +-
 net/sched/act_police.c     |  2 +-
 net/sched/act_sample.c     |  2 +-
 net/sched/act_simple.c     |  2 +-
 net/sched/act_skbedit.c    |  2 +-
 net/sched/act_skbmod.c     |  2 +-
 net/sched/act_tunnel_key.c |  2 +-
 net/sched/act_vlan.c       |  2 +-
 net/sched/cls_api.c        |  1 +
 net/sched/cls_basic.c      | 20 +++++++++++++++-----
 net/sched/cls_bpf.c        |  7 ++++++-
 net/sched/cls_cgroup.c     | 24 ++++++++++++++++++------
 net/sched/cls_flow.c       | 24 ++++++++++++++++++------
 net/sched/cls_flower.c     | 16 +++++++++++++---
 net/sched/cls_fw.c         | 17 ++++++++++++++---
 net/sched/cls_matchall.c   | 15 ++++++++++++---
 net/sched/cls_route.c      | 17 ++++++++++++++---
 net/sched/cls_rsvp.h       | 15 ++++++++++++---
 net/sched/cls_tcindex.c    | 33 ++++++++++++++++++++++++++-------
 net/sched/cls_u32.c        |  8 +++++++-
 31 files changed, 198 insertions(+), 63 deletions(-)

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2.13.0