From ed1481681414e4d4264ad46864d5c1da5ff6ccb1 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Mon, 6 Nov 2017 13:47:22 -0800 Subject: [PATCH] cls_cgroup: 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_cgroup.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c index a97e069bee89..309d5899265f 100644 --- a/net/sched/cls_cgroup.c +++ b/net/sched/cls_cgroup.c @@ -60,15 +60,21 @@ static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = { [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED }, }; +static void __cls_cgroup_destroy(struct cls_cgroup_head *head) +{ + tcf_exts_destroy(&head->exts); + tcf_em_tree_destroy(&head->ematches); + tcf_exts_put_net(&head->exts); + kfree(head); +} + static void cls_cgroup_destroy_work(struct work_struct *work) { struct cls_cgroup_head *head = container_of(work, struct cls_cgroup_head, work); rtnl_lock(); - tcf_exts_destroy(&head->exts); - tcf_em_tree_destroy(&head->ematches); - kfree(head); + __cls_cgroup_destroy(head); rtnl_unlock(); } @@ -124,8 +130,10 @@ static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb, goto errout; rcu_assign_pointer(tp->root, new); - if (head) + if (head) { + tcf_exts_get_net(&head->exts); call_rcu(&head->rcu, cls_cgroup_destroy_rcu); + } return 0; errout: tcf_exts_destroy(&new->exts); @@ -138,8 +146,12 @@ static void cls_cgroup_destroy(struct tcf_proto *tp) struct cls_cgroup_head *head = rtnl_dereference(tp->root); /* Head can still be NULL due to cls_cgroup_init(). */ - if (head) - call_rcu(&head->rcu, cls_cgroup_destroy_rcu); + if (head) { + if (tcf_exts_get_net(&head->exts)) + call_rcu(&head->rcu, cls_cgroup_destroy_rcu); + else + __cls_cgroup_destroy(head); + } } static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last) -- 2.20.1