ipv6: annotate data-races around cnf.disable_ipv6

disable_ipv6 is read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.

v2: do not preload net before rtnl_trylock() in
    addrconf_disable_ipv6() (Jiri)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2024-02-28 13:54:26 +00:00 committed by David S. Miller
parent 096361b155
commit d289ab65b8
3 changed files with 8 additions and 7 deletions

View File

@ -4214,7 +4214,7 @@ static void addrconf_dad_work(struct work_struct *w)
if (!ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) &&
ipv6_addr_equal(&ifp->addr, &addr)) {
/* DAD failed for link-local based on MAC */
idev->cnf.disable_ipv6 = 1;
WRITE_ONCE(idev->cnf.disable_ipv6, 1);
pr_info("%s: IPv6 being disabled!\n",
ifp->idev->dev->name);
@ -6389,7 +6389,8 @@ static void addrconf_disable_change(struct net *net, __s32 newf)
idev = __in6_dev_get(dev);
if (idev) {
int changed = (!idev->cnf.disable_ipv6) ^ (!newf);
idev->cnf.disable_ipv6 = newf;
WRITE_ONCE(idev->cnf.disable_ipv6, newf);
if (changed)
dev_disable_change(idev);
}
@ -6406,7 +6407,7 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf)
net = (struct net *)table->extra2;
old = *p;
*p = newf;
WRITE_ONCE(*p, newf);
if (p == &net->ipv6.devconf_dflt->disable_ipv6) {
rtnl_unlock();
@ -6414,7 +6415,7 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf)
}
if (p == &net->ipv6.devconf_all->disable_ipv6) {
net->ipv6.devconf_dflt->disable_ipv6 = newf;
WRITE_ONCE(net->ipv6.devconf_dflt->disable_ipv6, newf);
addrconf_disable_change(net, newf);
} else if ((!newf) ^ (!old))
dev_disable_change((struct inet6_dev *)table->extra1);

View File

@ -168,9 +168,9 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
SKB_DR_SET(reason, NOT_SPECIFIED);
if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
!idev || unlikely(idev->cnf.disable_ipv6)) {
!idev || unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {
__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
if (idev && unlikely(idev->cnf.disable_ipv6))
if (idev && unlikely(READ_ONCE(idev->cnf.disable_ipv6)))
SKB_DR_SET(reason, IPV6DISABLED);
goto drop;
}

View File

@ -234,7 +234,7 @@ int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
skb->protocol = htons(ETH_P_IPV6);
skb->dev = dev;
if (unlikely(idev->cnf.disable_ipv6)) {
if (unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {
IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);
return 0;