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

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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: e7614370d6 ("net_sched: use idr to allocate u32 filter handles")
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com>
Tested-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20241110172836.331319-1-alexandre.ferrieux@orange.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Alexandre Ferrieux 2024-11-10 18:28:36 +01:00 committed by Jakub Kicinski
parent 2b99b25325
commit 73af53d820
1 changed files with 14 additions and 4 deletions
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18
net/sched/cls_u32.c
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@ -92,6 +92,16 @@ struct tc_u_common {
long knodes; 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, static inline unsigned int u32_hash_fold(__be32 key,
const struct tc_u32_sel *sel, const struct tc_u32_sel *sel,
u8 fshift) 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); int id = idr_alloc_cyclic(&tp_c->handle_idr, ptr, 1, 0x7FF, GFP_KERNEL);
if (id < 0) if (id < 0)
return 0; return 0;
return (id | 0x800U) << 20; return id2handle(id);
} }
static struct hlist_head *tc_u_common_hash; static struct hlist_head *tc_u_common_hash;
@ -360,7 +370,7 @@ static int u32_init(struct tcf_proto *tp)
return -ENOBUFS; return -ENOBUFS;
refcount_set(&root_ht->refcnt, 1); 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->prio = tp->prio;
root_ht->is_root = true; root_ht->is_root = true;
idr_init(&root_ht->handle_idr); 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) { if (phn == ht) {
u32_clear_hw_hnode(tp, ht, extack); u32_clear_hw_hnode(tp, ht, extack);
idr_destroy(&ht->handle_idr); 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); RCU_INIT_POINTER(*hn, ht->next);
kfree_rcu(ht, rcu); kfree_rcu(ht, rcu);
return 0; 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); err = u32_replace_hw_hnode(tp, ht, userflags, extack);
if (err) { if (err) {
idr_remove(&tp_c->handle_idr, handle); idr_remove(&tp_c->handle_idr, handle2id(handle));
kfree(ht); kfree(ht);
return err; return err;
} }