From 94cdb47566b799649e996e1fb9de2a503dada763 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Thu, 26 Oct 2017 18:24:32 -0700 Subject: net_sched: use tcf_queue_work() in flow filter Defer the tcf_exts_destroy() in RCU callback to tc filter workqueue and get RTNL lock. Reported-by: Chris Mi Cc: Daniel Borkmann Cc: Jiri Pirko Cc: John Fastabend Cc: Jamal Hadi Salim Cc: "Paul E. McKenney" Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/cls_flow.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'net/sched/cls_flow.c') diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c index 2a3a60ec5b86..67f3a2af6aab 100644 --- a/net/sched/cls_flow.c +++ b/net/sched/cls_flow.c @@ -57,7 +57,10 @@ struct flow_filter { u32 divisor; u32 baseclass; u32 hashrnd; - struct rcu_head rcu; + union { + struct work_struct work; + struct rcu_head rcu; + }; }; static inline u32 addr_fold(void *addr) @@ -369,14 +372,24 @@ static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = { [TCA_FLOW_PERTURB] = { .type = NLA_U32 }, }; -static void flow_destroy_filter(struct rcu_head *head) +static void flow_destroy_filter_work(struct work_struct *work) { - struct flow_filter *f = container_of(head, struct flow_filter, rcu); + struct flow_filter *f = container_of(work, struct flow_filter, work); + rtnl_lock(); del_timer_sync(&f->perturb_timer); tcf_exts_destroy(&f->exts); tcf_em_tree_destroy(&f->ematches); kfree(f); + rtnl_unlock(); +} + +static void flow_destroy_filter(struct rcu_head *head) +{ + struct flow_filter *f = container_of(head, struct flow_filter, rcu); + + INIT_WORK(&f->work, flow_destroy_filter_work); + tcf_queue_work(&f->work); } static int flow_change(struct net *net, struct sk_buff *in_skb, -- cgit v1.2.3 From 22f7cec93f0af86c4b66bf34a977da9d7cef076e Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Mon, 6 Nov 2017 13:47:23 -0800 Subject: cls_flow: use tcf_exts_get_net() before call_rcu() Hold netns refcnt before call_rcu() and release it after the tcf_exts_destroy() is done. Note, on ->destroy() path we have to respect the return value of tcf_exts_get_net(), on other paths it should always return true, so we don't need to care. Cc: Lucas Bates Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/cls_flow.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) (limited to 'net/sched/cls_flow.c') diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c index 67f3a2af6aab..85f765cff697 100644 --- a/net/sched/cls_flow.c +++ b/net/sched/cls_flow.c @@ -372,15 +372,21 @@ static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = { [TCA_FLOW_PERTURB] = { .type = NLA_U32 }, }; -static void flow_destroy_filter_work(struct work_struct *work) +static void __flow_destroy_filter(struct flow_filter *f) { - struct flow_filter *f = container_of(work, struct flow_filter, work); - - rtnl_lock(); del_timer_sync(&f->perturb_timer); tcf_exts_destroy(&f->exts); tcf_em_tree_destroy(&f->ematches); + tcf_exts_put_net(&f->exts); kfree(f); +} + +static void flow_destroy_filter_work(struct work_struct *work) +{ + struct flow_filter *f = container_of(work, struct flow_filter, work); + + rtnl_lock(); + __flow_destroy_filter(f); rtnl_unlock(); } @@ -552,8 +558,10 @@ static int flow_change(struct net *net, struct sk_buff *in_skb, *arg = fnew; - if (fold) + if (fold) { + tcf_exts_get_net(&fold->exts); call_rcu(&fold->rcu, flow_destroy_filter); + } return 0; err2: @@ -570,6 +578,7 @@ static int flow_delete(struct tcf_proto *tp, void *arg, bool *last) struct flow_filter *f = arg; list_del_rcu(&f->list); + tcf_exts_get_net(&f->exts); call_rcu(&f->rcu, flow_destroy_filter); *last = list_empty(&head->filters); return 0; @@ -594,7 +603,10 @@ static void flow_destroy(struct tcf_proto *tp) list_for_each_entry_safe(f, next, &head->filters, list) { list_del_rcu(&f->list); - call_rcu(&f->rcu, flow_destroy_filter); + if (tcf_exts_get_net(&f->exts)) + call_rcu(&f->rcu, flow_destroy_filter); + else + __flow_destroy_filter(f); } kfree_rcu(head, rcu); } -- cgit v1.2.3