Commit 73af53d8 authored by Alexandre Ferrieux's avatar Alexandre Ferrieux Committed by Jakub Kicinski
Browse files

net: sched: cls_u32: Fix u32's systematic failure to free IDR entries for hnodes. 



To generate hnode handles (in gen_new_htid()), u32 uses IDR and
encodes the returned small integer into a structured 32-bit
word. Unfortunately, at disposal time, the needed decoding
is not done. As a result, idr_remove() fails, and the IDR
fills up. Since its size is 2048, the following script ends up
with "Filter already exists":

  tc filter add dev myve $FILTER1
  tc filter add dev myve $FILTER2
  for i in {1..2048}
  do
    echo $i
    tc filter del dev myve $FILTER2
    tc filter add dev myve $FILTER2
  done

This patch adds the missing decoding logic for handles that
deserve it.

Fixes: e7614370 ("net_sched: use idr to allocate u32 filter handles")
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: default avatarAlexandre Ferrieux <alexandre.ferrieux@orange.com>
Tested-by: default avatarVictor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20241110172836.331319-1-alexandre.ferrieux@orange.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 2b99b253

net/sched/cls_u32.c

+14 −4
Original line number Diff line number Diff line
@@ -92,6 +92,16 @@ struct tc_u_common { 
	long			knodes;

};



static u32 handle2id(u32 h)

{

	return ((h & 0x80000000) ? ((h >> 20) & 0x7FF) : h);

}



static u32 id2handle(u32 id)

{

	return (id | 0x800U) << 20;

}



static inline unsigned int u32_hash_fold(__be32 key,

					 const struct tc_u32_sel *sel,

					 u8 fshift)
@@ -310,7 +320,7 @@ static u32 gen_new_htid(struct tc_u_common *tp_c, struct tc_u_hnode *ptr) 
	int id = idr_alloc_cyclic(&tp_c->handle_idr, ptr, 1, 0x7FF, GFP_KERNEL);

	if (id < 0)

		return 0;

	return (id | 0x800U) << 20;

	return id2handle(id);

}



static struct hlist_head *tc_u_common_hash;
@@ -360,7 +370,7 @@ static int u32_init(struct tcf_proto *tp) 
		return -ENOBUFS;



	refcount_set(&root_ht->refcnt, 1);

	root_ht->handle = tp_c ? gen_new_htid(tp_c, root_ht) : 0x80000000;

	root_ht->handle = tp_c ? gen_new_htid(tp_c, root_ht) : id2handle(0);

	root_ht->prio = tp->prio;

	root_ht->is_root = true;

	idr_init(&root_ht->handle_idr);
@@ -612,7 +622,7 @@ static int u32_destroy_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht, 
		if (phn == ht) {

			u32_clear_hw_hnode(tp, ht, extack);

			idr_destroy(&ht->handle_idr);

			idr_remove(&tp_c->handle_idr, ht->handle);

			idr_remove(&tp_c->handle_idr, handle2id(ht->handle));

			RCU_INIT_POINTER(*hn, ht->next);

			kfree_rcu(ht, rcu);

			return 0;
@@ -989,7 +999,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb, 


		err = u32_replace_hw_hnode(tp, ht, userflags, extack);

		if (err) {

			idr_remove(&tp_c->handle_idr, handle);

			idr_remove(&tp_c->handle_idr, handle2id(handle));

			kfree(ht);

			return err;

		}