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cls_u32: use tcf_exts_get_net() before call_rcu()
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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 <[email protected]>
Cc: Jamal Hadi Salim <[email protected]>
Cc: Jiri Pirko <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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congwang authored and davem330 committed Nov 9, 2017
1 parent f2b7510 commit 35c55fc
Showing 1 changed file with 7 additions and 1 deletion.
8 changes: 7 additions & 1 deletion net/sched/cls_u32.c
Original file line number Diff line number Diff line change
Expand Up @@ -399,6 +399,7 @@ static int u32_destroy_key(struct tcf_proto *tp, struct tc_u_knode *n,
bool free_pf)
{
tcf_exts_destroy(&n->exts);
tcf_exts_put_net(&n->exts);
if (n->ht_down)
n->ht_down->refcnt--;
#ifdef CONFIG_CLS_U32_PERF
Expand Down Expand Up @@ -476,6 +477,7 @@ static int u32_delete_key(struct tcf_proto *tp, struct tc_u_knode *key)
RCU_INIT_POINTER(*kp, key->next);

tcf_unbind_filter(tp, &key->res);
tcf_exts_get_net(&key->exts);
call_rcu(&key->rcu, u32_delete_key_freepf_rcu);
return 0;
}
Expand Down Expand Up @@ -588,7 +590,10 @@ static void u32_clear_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht)
rtnl_dereference(n->next));
tcf_unbind_filter(tp, &n->res);
u32_remove_hw_knode(tp, n->handle);
call_rcu(&n->rcu, u32_delete_key_freepf_rcu);
if (tcf_exts_get_net(&n->exts))
call_rcu(&n->rcu, u32_delete_key_freepf_rcu);
else
u32_destroy_key(n->tp, n, true);
}
}
}
Expand Down Expand Up @@ -949,6 +954,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,

u32_replace_knode(tp, tp_c, new);
tcf_unbind_filter(tp, &n->res);
tcf_exts_get_net(&n->exts);
call_rcu(&n->rcu, u32_delete_key_rcu);
return 0;
}
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