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 <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>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
index 67f3a2a..85f765c 100644
--- a/net/sched/cls_flow.c
+++ b/net/sched/cls_flow.c
@@ -372,15 +372,21 @@
[TCA_FLOW_PERTURB] = { .type = NLA_U32 },
};
+static void __flow_destroy_filter(struct flow_filter *f)
+{
+ 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();
- del_timer_sync(&f->perturb_timer);
- tcf_exts_destroy(&f->exts);
- tcf_em_tree_destroy(&f->ematches);
- kfree(f);
+ __flow_destroy_filter(f);
rtnl_unlock();
}
@@ -552,8 +558,10 @@
*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 @@
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 @@
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);
}
