| Message ID | 20241101184309.231941-1-alexandre.ferrieux@orange.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] Fix u32's systematic failure to free IDR entries for hnodes. | expand |
On Fri, Nov 1, 2024 at 7:43 PM Alexandre Ferrieux <alexandre.ferrieux@gmail.com> wrote: > > To generate hnode handles (in gen_new_htid()), u32 uses IDR and > encodes the returned small integer into a strucured 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. > > Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com> > --- $ scripts/get_maintainer.pl net/sched/cls_u32.c -> Jamal Hadi Salim <jhs@mojatatu.com> (maintainer:TC subsystem) Cong Wang <xiyou.wangcong@gmail.com> (maintainer:TC subsystem) Jiri Pirko <jiri@resnulli.us> (maintainer:TC subsystem) Please resend adding them to get their feedback ? Thank you. > net/sched/cls_u32.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c > index 9412d88a99bc..54b5fca623da 100644 > --- a/net/sched/cls_u32.c > +++ b/net/sched/cls_u32.c > @@ -41,6 +41,16 @@ > #include <linux/idr.h> > #include <net/tc_wrapper.h> > > +static inline unsigned int handle2id(unsigned int h) > +{ > + return ((h & 0x80000000) ? ((h >> 20) & 0x7FF) : h); > +} > + > +static inline unsigned int id2handle(unsigned int id) > +{ > + return (id | 0x800U) << 20; > +} > + > struct tc_u_knode { > struct tc_u_knode __rcu *next; > u32 handle; > @@ -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; > } > -- > 2.30.2 >
diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 9412d88a99bc..54b5fca623da 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -41,6 +41,16 @@ #include <linux/idr.h> #include <net/tc_wrapper.h> +static inline unsigned int handle2id(unsigned int h) +{ + return ((h & 0x80000000) ? ((h >> 20) & 0x7FF) : h); +} + +static inline unsigned int id2handle(unsigned int id) +{ + return (id | 0x800U) << 20; +} + struct tc_u_knode { struct tc_u_knode __rcu *next; u32 handle; @@ -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; }
To generate hnode handles (in gen_new_htid()), u32 uses IDR and encodes the returned small integer into a strucured 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. Signed-off-by: Alexandre Ferrieux <alexandre.ferrieux@orange.com> --- net/sched/cls_u32.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)