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neighbour: annotate lockless accesses to n->nud_state

Browse Source 
We have many lockless accesses to n->nud_state.

Before adding another one in the following patch,
add annotations to readers and writers.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2023-03-13 20:17:31 +00:00 committed by Jakub Kicinski
parent 68a84a127b
commit b071af5235
13 changed files with 36 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/net/vxlan/vxlan_core.c
View File

@ -1863,7 +1863,7 @@ static int arp_reduce(struct net_device *dev, struct sk_buff *skb, __be32 vni)
struct vxlan_fdb *f; struct vxlan_fdb *f;
struct sk_buff *reply; struct sk_buff *reply;
if (!(n->nud_state & NUD_CONNECTED)) { if (!(READ_ONCE(n->nud_state) & NUD_CONNECTED)) {
neigh_release(n); neigh_release(n);
goto out; goto out;
} }
@ -2027,7 +2027,7 @@ static int neigh_reduce(struct net_device *dev, struct sk_buff *skb, __be32 vni)
struct vxlan_fdb *f; struct vxlan_fdb *f;
struct sk_buff *reply; struct sk_buff *reply;
if (!(n->nud_state & NUD_CONNECTED)) { if (!(READ_ONCE(n->nud_state) & NUD_CONNECTED)) {
neigh_release(n); neigh_release(n);
goto out; goto out;
} }

2
include/net/neighbour.h
View File

@ -464,7 +464,7 @@ static __always_inline int neigh_event_send_probe(struct neighbour *neigh,
if (READ_ONCE(neigh->used) != now) if (READ_ONCE(neigh->used) != now)
WRITE_ONCE(neigh->used, now); WRITE_ONCE(neigh->used, now);
if (!(neigh->nud_state & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE))) if (!(READ_ONCE(neigh->nud_state) & (NUD_CONNECTED | NUD_DELAY | NUD_PROBE)))
return __neigh_event_send(neigh, skb, immediate_ok); return __neigh_event_send(neigh, skb, immediate_ok);
return 0; return 0;
} }

4
net/bridge/br_arp_nd_proxy.c
View File

@ -192,7 +192,7 @@ void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br,
if (n) { if (n) {
struct net_bridge_fdb_entry *f; struct net_bridge_fdb_entry *f;
if (!(n->nud_state & NUD_VALID)) { if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
neigh_release(n); neigh_release(n);
return; return;
} }
@ -452,7 +452,7 @@ void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br,
if (n) { if (n) {
struct net_bridge_fdb_entry *f; struct net_bridge_fdb_entry *f;
if (!(n->nud_state & NUD_VALID)) { if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
neigh_release(n); neigh_release(n);
return; return;
} }

3
net/bridge/br_netfilter_hooks.c
View File

@ -277,7 +277,8 @@ int br_nf_pre_routing_finish_bridge(struct net *net, struct sock *sk, struct sk_
struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb); struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
int ret; int ret;
if ((neigh->nud_state & NUD_CONNECTED) && neigh->hh.hh_len) { if ((READ_ONCE(neigh->nud_state) & NUD_CONNECTED) &&
READ_ONCE(neigh->hh.hh_len)) {
neigh_hh_bridge(&neigh->hh, skb); neigh_hh_bridge(&neigh->hh, skb);
skb->dev = nf_bridge->physindev; skb->dev = nf_bridge->physindev;
ret = br_handle_frame_finish(net, sk, skb); ret = br_handle_frame_finish(net, sk, skb);

4
net/core/filter.c
View File

@ -5871,7 +5871,7 @@ static int bpf_ipv4_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
else else
neigh = __ipv6_neigh_lookup_noref_stub(dev, params->ipv6_dst); neigh = __ipv6_neigh_lookup_noref_stub(dev, params->ipv6_dst);
if (!neigh || !(neigh->nud_state & NUD_VALID)) if (!neigh || !(READ_ONCE(neigh->nud_state) & NUD_VALID))
return BPF_FIB_LKUP_RET_NO_NEIGH; return BPF_FIB_LKUP_RET_NO_NEIGH;
memcpy(params->dmac, neigh->ha, ETH_ALEN); memcpy(params->dmac, neigh->ha, ETH_ALEN);
memcpy(params->smac, dev->dev_addr, ETH_ALEN); memcpy(params->smac, dev->dev_addr, ETH_ALEN);
@ -5992,7 +5992,7 @@ static int bpf_ipv6_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
* not needed here. * not needed here.
*/ */
neigh = __ipv6_neigh_lookup_noref_stub(dev, dst); neigh = __ipv6_neigh_lookup_noref_stub(dev, dst);
if (!neigh || !(neigh->nud_state & NUD_VALID)) if (!neigh || !(READ_ONCE(neigh->nud_state) & NUD_VALID))
return BPF_FIB_LKUP_RET_NO_NEIGH; return BPF_FIB_LKUP_RET_NO_NEIGH;
memcpy(params->dmac, neigh->ha, ETH_ALEN); memcpy(params->dmac, neigh->ha, ETH_ALEN);
memcpy(params->smac, dev->dev_addr, ETH_ALEN); memcpy(params->smac, dev->dev_addr, ETH_ALEN);

28
net/core/neighbour.c
View File

@ -1093,13 +1093,13 @@ static void neigh_timer_handler(struct timer_list *t)
neigh->used + neigh->used +
NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME))) { NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME))) {
neigh_dbg(2, "neigh %p is delayed\n", neigh); neigh_dbg(2, "neigh %p is delayed\n", neigh);
neigh->nud_state = NUD_DELAY; WRITE_ONCE(neigh->nud_state, NUD_DELAY);
neigh->updated = jiffies; neigh->updated = jiffies;
neigh_suspect(neigh); neigh_suspect(neigh);
next = now + NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME); next = now + NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME);
} else { } else {
neigh_dbg(2, "neigh %p is suspected\n", neigh); neigh_dbg(2, "neigh %p is suspected\n", neigh);
neigh->nud_state = NUD_STALE; WRITE_ONCE(neigh->nud_state, NUD_STALE);
neigh->updated = jiffies; neigh->updated = jiffies;
neigh_suspect(neigh); neigh_suspect(neigh);
notify = 1; notify = 1;
@ -1109,14 +1109,14 @@ static void neigh_timer_handler(struct timer_list *t)
neigh->confirmed + neigh->confirmed +
NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME))) { NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME))) {
neigh_dbg(2, "neigh %p is now reachable\n", neigh); neigh_dbg(2, "neigh %p is now reachable\n", neigh);
neigh->nud_state = NUD_REACHABLE; WRITE_ONCE(neigh->nud_state, NUD_REACHABLE);
neigh->updated = jiffies; neigh->updated = jiffies;
neigh_connect(neigh); neigh_connect(neigh);
notify = 1; notify = 1;
next = neigh->confirmed + neigh->parms->reachable_time; next = neigh->confirmed + neigh->parms->reachable_time;
} else { } else {
neigh_dbg(2, "neigh %p is probed\n", neigh); neigh_dbg(2, "neigh %p is probed\n", neigh);
neigh->nud_state = NUD_PROBE; WRITE_ONCE(neigh->nud_state, NUD_PROBE);
neigh->updated = jiffies; neigh->updated = jiffies;
atomic_set(&neigh->probes, 0); atomic_set(&neigh->probes, 0);
notify = 1; notify = 1;
@ -1130,7 +1130,7 @@ static void neigh_timer_handler(struct timer_list *t)
if ((neigh->nud_state & (NUD_INCOMPLETE | NUD_PROBE)) && if ((neigh->nud_state & (NUD_INCOMPLETE | NUD_PROBE)) &&
atomic_read(&neigh->probes) >= neigh_max_probes(neigh)) { atomic_read(&neigh->probes) >= neigh_max_probes(neigh)) {
neigh->nud_state = NUD_FAILED; WRITE_ONCE(neigh->nud_state, NUD_FAILED);
notify = 1; notify = 1;
neigh_invalidate(neigh); neigh_invalidate(neigh);
goto out; goto out;
@ -1179,7 +1179,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
atomic_set(&neigh->probes, atomic_set(&neigh->probes,
NEIGH_VAR(neigh->parms, UCAST_PROBES)); NEIGH_VAR(neigh->parms, UCAST_PROBES));
neigh_del_timer(neigh); neigh_del_timer(neigh);
neigh->nud_state = NUD_INCOMPLETE; WRITE_ONCE(neigh->nud_state, NUD_INCOMPLETE);
neigh->updated = now; neigh->updated = now;
if (!immediate_ok) { if (!immediate_ok) {
next = now + 1; next = now + 1;
@ -1191,7 +1191,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
} }
neigh_add_timer(neigh, next); neigh_add_timer(neigh, next);
} else { } else {
neigh->nud_state = NUD_FAILED; WRITE_ONCE(neigh->nud_state, NUD_FAILED);
neigh->updated = jiffies; neigh->updated = jiffies;
write_unlock_bh(&neigh->lock); write_unlock_bh(&neigh->lock);
@ -1201,7 +1201,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb,
} else if (neigh->nud_state & NUD_STALE) { } else if (neigh->nud_state & NUD_STALE) {
neigh_dbg(2, "neigh %p is delayed\n", neigh); neigh_dbg(2, "neigh %p is delayed\n", neigh);
neigh_del_timer(neigh); neigh_del_timer(neigh);
neigh->nud_state = NUD_DELAY; WRITE_ONCE(neigh->nud_state, NUD_DELAY);
neigh->updated = jiffies; neigh->updated = jiffies;
neigh_add_timer(neigh, jiffies + neigh_add_timer(neigh, jiffies +
NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME)); NEIGH_VAR(neigh->parms, DELAY_PROBE_TIME));
@ -1313,7 +1313,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
neigh_update_flags(neigh, flags, &notify, &gc_update, &managed_update); neigh_update_flags(neigh, flags, &notify, &gc_update, &managed_update);
if (flags & (NEIGH_UPDATE_F_USE | NEIGH_UPDATE_F_MANAGED)) { if (flags & (NEIGH_UPDATE_F_USE | NEIGH_UPDATE_F_MANAGED)) {
new = old & ~NUD_PERMANENT; new = old & ~NUD_PERMANENT;
neigh->nud_state = new; WRITE_ONCE(neigh->nud_state, new);
err = 0; err = 0;
goto out; goto out;
} }
@ -1322,7 +1322,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
neigh_del_timer(neigh); neigh_del_timer(neigh);
if (old & NUD_CONNECTED) if (old & NUD_CONNECTED)
neigh_suspect(neigh); neigh_suspect(neigh);
neigh->nud_state = new; WRITE_ONCE(neigh->nud_state, new);
err = 0; err = 0;
notify = old & NUD_VALID; notify = old & NUD_VALID;
if ((old & (NUD_INCOMPLETE | NUD_PROBE)) && if ((old & (NUD_INCOMPLETE | NUD_PROBE)) &&
@ -1401,7 +1401,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr,
((new & NUD_REACHABLE) ? ((new & NUD_REACHABLE) ?
neigh->parms->reachable_time : neigh->parms->reachable_time :
0))); 0)));
neigh->nud_state = new; WRITE_ONCE(neigh->nud_state, new);
notify = 1; notify = 1;
} }
@ -1488,7 +1488,7 @@ void __neigh_set_probe_once(struct neighbour *neigh)
neigh->updated = jiffies; neigh->updated = jiffies;
if (!(neigh->nud_state & NUD_FAILED)) if (!(neigh->nud_state & NUD_FAILED))
return; return;
neigh->nud_state = NUD_INCOMPLETE; WRITE_ONCE(neigh->nud_state, NUD_INCOMPLETE);
atomic_set(&neigh->probes, neigh_max_probes(neigh)); atomic_set(&neigh->probes, neigh_max_probes(neigh));
neigh_add_timer(neigh, neigh_add_timer(neigh,
jiffies + max(NEIGH_VAR(neigh->parms, RETRANS_TIME), jiffies + max(NEIGH_VAR(neigh->parms, RETRANS_TIME),
@ -3198,7 +3198,7 @@ static struct neighbour *neigh_get_first(struct seq_file *seq)
} }
if (!(state->flags & NEIGH_SEQ_SKIP_NOARP)) if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
break; break;
if (n->nud_state & ~NUD_NOARP) if (READ_ONCE(n->nud_state) & ~NUD_NOARP)
break; break;
next: next:
n = rcu_dereference_bh(n->next); n = rcu_dereference_bh(n->next);
@ -3240,7 +3240,7 @@ static struct neighbour *neigh_get_next(struct seq_file *seq,
if (!(state->flags & NEIGH_SEQ_SKIP_NOARP)) if (!(state->flags & NEIGH_SEQ_SKIP_NOARP))
break; break;
if (n->nud_state & ~NUD_NOARP) if (READ_ONCE(n->nud_state) & ~NUD_NOARP)
break; break;
next: next:
n = rcu_dereference_bh(n->next); n = rcu_dereference_bh(n->next);

8
net/ipv4/arp.c
View File

@ -375,7 +375,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
if (probes < 0) { if (probes < 0) {
if (!(neigh->nud_state & NUD_VALID)) if (!(READ_ONCE(neigh->nud_state) & NUD_VALID))
pr_debug("trying to ucast probe in NUD_INVALID\n"); pr_debug("trying to ucast probe in NUD_INVALID\n");
neigh_ha_snapshot(dst_ha, neigh, dev); neigh_ha_snapshot(dst_ha, neigh, dev);
dst_hw = dst_ha; dst_hw = dst_ha;
@ -1123,7 +1123,7 @@ static int arp_req_get(struct arpreq *r, struct net_device *dev)
neigh = neigh_lookup(&arp_tbl, &ip, dev); neigh = neigh_lookup(&arp_tbl, &ip, dev);
if (neigh) { if (neigh) {
if (!(neigh->nud_state & NUD_NOARP)) { if (!(READ_ONCE(neigh->nud_state) & NUD_NOARP)) {
read_lock_bh(&neigh->lock); read_lock_bh(&neigh->lock);
memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len); memcpy(r->arp_ha.sa_data, neigh->ha, dev->addr_len);
r->arp_flags = arp_state_to_flags(neigh); r->arp_flags = arp_state_to_flags(neigh);
@ -1144,12 +1144,12 @@ int arp_invalidate(struct net_device *dev, __be32 ip, bool force)
struct neigh_table *tbl = &arp_tbl; struct neigh_table *tbl = &arp_tbl;
if (neigh) { if (neigh) {
if ((neigh->nud_state & NUD_VALID) && !force) { if ((READ_ONCE(neigh->nud_state) & NUD_VALID) && !force) {
neigh_release(neigh); neigh_release(neigh);
return 0; return 0;
} }
if (neigh->nud_state & ~NUD_NOARP) if (READ_ONCE(neigh->nud_state) & ~NUD_NOARP)
err = neigh_update(neigh, NULL, NUD_FAILED, err = neigh_update(neigh, NULL, NUD_FAILED,
NEIGH_UPDATE_F_OVERRIDE| NEIGH_UPDATE_F_OVERRIDE|
NEIGH_UPDATE_F_ADMIN, 0); NEIGH_UPDATE_F_ADMIN, 0);

4
net/ipv4/fib_semantics.c
View File

@ -563,7 +563,7 @@ static int fib_detect_death(struct fib_info *fi, int order,
n = NULL; n = NULL;
if (n) { if (n) {
state = n->nud_state; state = READ_ONCE(n->nud_state);
neigh_release(n); neigh_release(n);
} else { } else {
return 0; return 0;
@ -2202,7 +2202,7 @@ static bool fib_good_nh(const struct fib_nh *nh)
else else
n = NULL; n = NULL;
if (n) if (n)
state = n->nud_state; state = READ_ONCE(n->nud_state);
rcu_read_unlock_bh(); rcu_read_unlock_bh();
} }

4
net/ipv4/nexthop.c
View File

@ -1128,7 +1128,7 @@ static bool ipv6_good_nh(const struct fib6_nh *nh)
n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6); n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev, &nh->fib_nh_gw6);
if (n) if (n)
state = n->nud_state; state = READ_ONCE(n->nud_state);
rcu_read_unlock_bh(); rcu_read_unlock_bh();
@ -1145,7 +1145,7 @@ static bool ipv4_good_nh(const struct fib_nh *nh)
n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev, n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
(__force u32)nh->fib_nh_gw4); (__force u32)nh->fib_nh_gw4);
if (n) if (n)
state = n->nud_state; state = READ_ONCE(n->nud_state);
rcu_read_unlock_bh(); rcu_read_unlock_bh();

2
net/ipv4/route.c
View File

@ -784,7 +784,7 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow
if (!n) if (!n)
n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev); n = neigh_create(&arp_tbl, &new_gw, rt->dst.dev);
if (!IS_ERR(n)) { if (!IS_ERR(n)) {
if (!(n->nud_state & NUD_VALID)) { if (!(READ_ONCE(n->nud_state) & NUD_VALID)) {
neigh_event_send(n, NULL); neigh_event_send(n, NULL);
} else { } else {
if (fib_lookup(net, fl4, &res, 0) == 0) { if (fib_lookup(net, fl4, &res, 0) == 0) {

2
net/ipv6/ip6_output.c
View File

@ -1153,7 +1153,7 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
rcu_read_lock_bh(); rcu_read_lock_bh();
n = __ipv6_neigh_lookup_noref(rt->dst.dev, n = __ipv6_neigh_lookup_noref(rt->dst.dev,
rt6_nexthop(rt, &fl6->daddr)); rt6_nexthop(rt, &fl6->daddr));
err = n && !(n->nud_state & NUD_VALID) ? -EINVAL : 0; err = n && !(READ_ONCE(n->nud_state) & NUD_VALID) ? -EINVAL : 0;
rcu_read_unlock_bh(); rcu_read_unlock_bh();
if (err) { if (err) {

4
net/ipv6/ndisc.c
View File

@ -745,7 +745,7 @@ static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb)
saddr = &ipv6_hdr(skb)->saddr; saddr = &ipv6_hdr(skb)->saddr;
probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES); probes -= NEIGH_VAR(neigh->parms, UCAST_PROBES);
if (probes < 0) { if (probes < 0) {
if (!(neigh->nud_state & NUD_VALID)) { if (!(READ_ONCE(neigh->nud_state) & NUD_VALID)) {
ND_PRINTK(1, dbg, ND_PRINTK(1, dbg,
"%s: trying to ucast probe in NUD_INVALID: %pI6\n", "%s: trying to ucast probe in NUD_INVALID: %pI6\n",
__func__, target); __func__, target);
@ -1090,7 +1090,7 @@ static enum skb_drop_reason ndisc_recv_na(struct sk_buff *skb)
u8 old_flags = neigh->flags; u8 old_flags = neigh->flags;
struct net *net = dev_net(dev); struct net *net = dev_net(dev);
if (neigh->nud_state & NUD_FAILED) if (READ_ONCE(neigh->nud_state) & NUD_FAILED)
goto out; goto out;
/* /*

2
net/ipv6/route.c
View File

@ -638,7 +638,7 @@ static void rt6_probe(struct fib6_nh *fib6_nh)
idev = __in6_dev_get(dev); idev = __in6_dev_get(dev);
neigh = __ipv6_neigh_lookup_noref(dev, nh_gw); neigh = __ipv6_neigh_lookup_noref(dev, nh_gw);
if (neigh) { if (neigh) {
if (neigh->nud_state & NUD_VALID) if (READ_ONCE(neigh->nud_state) & NUD_VALID)
goto out; goto out;
write_lock(&neigh->lock); write_lock(&neigh->lock);