diff options
| author | Cong Wang <xiyou.wangcong@gmail.com> | 2017-12-20 23:26:24 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-12-26 12:28:40 -0500 |
| commit | b2fb01f426883a794ed80be9110675a2d8356347 (patch) | |
| tree | 27c6f9bc0269903fe480f9a69530fd3ea0e08d22 /net | |
| parent | c1a8d0a3accf64a014d605e6806ce05d1c17adf1 (diff) | |
net_sched: fix a missing rcu barrier in mini_qdisc_pair_swap()
The rcu_barrier_bh() in mini_qdisc_pair_swap() is to wait for
flying RCU callback installed by a previous mini_qdisc_pair_swap(),
however we miss it on the tp_head==NULL path, which leads to that
the RCU callback still uses miniq_old->rcu after it is freed together
with qdisc in qdisc_graft(). So just add it on that path too.
Fixes: 46209401f8f6 ("net: core: introduce mini_Qdisc and eliminate usage of tp->q for clsact fastpath ")
Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Tested-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/sched/sch_generic.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index cd1b200acae7..661c7144b53a 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -1040,6 +1040,8 @@ void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp, if (!tp_head) { RCU_INIT_POINTER(*miniqp->p_miniq, NULL); + /* Wait for flying RCU callback before it is freed. */ + rcu_barrier_bh(); return; } @@ -1055,7 +1057,7 @@ void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp, rcu_assign_pointer(*miniqp->p_miniq, miniq); if (miniq_old) - /* This is counterpart of the rcu barrier above. We need to + /* This is counterpart of the rcu barriers above. We need to * block potential new user of miniq_old until all readers * are not seeing it. */ |