The following commit has been merged in the master branch: commit 145c7a793838add5e004e7d49a67654dc7eba147 Author: Eric Dumazet edumazet@google.com Date: Fri Feb 4 12:15:45 2022 -0800

ipv6: make mc_forwarding atomic

This fixes minor data-races in ip6_mc_input() and batadv_mcast_mla_rtr_flags_softif_get_ipv6()

Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 1e0f8a31f3de..16870f86c74d 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -51,7 +51,7 @@ struct ipv6_devconf { __s32 use_optimistic; #endif #ifdef CONFIG_IPV6_MROUTE - __s32 mc_forwarding; + atomic_t mc_forwarding; #endif __s32 disable_ipv6; __s32 drop_unicast_in_l2_multicast; diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c index f4004cf0ff6f..9f311fddfaf9 100644 --- a/net/batman-adv/multicast.c +++ b/net/batman-adv/multicast.c @@ -134,7 +134,7 @@ static u8 batadv_mcast_mla_rtr_flags_softif_get_ipv6(struct net_device *dev) { struct inet6_dev *in6_dev = __in6_dev_get(dev);

- if (in6_dev && in6_dev->cnf.mc_forwarding) + if (in6_dev && atomic_read(&in6_dev->cnf.mc_forwarding)) return BATADV_NO_FLAGS; else return BATADV_MCAST_WANT_NO_RTR6; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index f927c199a93c..ff1b2484b8ed 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -554,7 +554,7 @@ static int inet6_netconf_fill_devconf(struct sk_buff *skb, int ifindex, #ifdef CONFIG_IPV6_MROUTE if ((all || type == NETCONFA_MC_FORWARDING) && nla_put_s32(skb, NETCONFA_MC_FORWARDING, - devconf->mc_forwarding) < 0) + atomic_read(&devconf->mc_forwarding)) < 0) goto nla_put_failure; #endif if ((all || type == NETCONFA_PROXY_NEIGH) && @@ -5533,7 +5533,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf, array[DEVCONF_USE_OPTIMISTIC] = cnf->use_optimistic; #endif #ifdef CONFIG_IPV6_MROUTE - array[DEVCONF_MC_FORWARDING] = cnf->mc_forwarding; + array[DEVCONF_MC_FORWARDING] = atomic_read(&cnf->mc_forwarding); #endif array[DEVCONF_DISABLE_IPV6] = cnf->disable_ipv6; array[DEVCONF_ACCEPT_DAD] = cnf->accept_dad; diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c index 80256717868e..d4b1e2c5aa76 100644 --- a/net/ipv6/ip6_input.c +++ b/net/ipv6/ip6_input.c @@ -508,7 +508,7 @@ int ip6_mc_input(struct sk_buff *skb) /* * IPv6 multicast router mode is now supported ;) */ - if (dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding && + if (atomic_read(&dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding) && !(ipv6_addr_type(&hdr->daddr) & (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) && likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) { diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 7cf73e60e619..541cd0887129 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -732,7 +732,7 @@ static int mif6_delete(struct mr_table *mrt, int vifi, int notify,

in6_dev = __in6_dev_get(dev); if (in6_dev) { - in6_dev->cnf.mc_forwarding--; + atomic_dec(&in6_dev->cnf.mc_forwarding); inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF, NETCONFA_MC_FORWARDING, dev->ifindex, &in6_dev->cnf); @@ -900,7 +900,7 @@ static int mif6_add(struct net *net, struct mr_table *mrt,

in6_dev = __in6_dev_get(dev); if (in6_dev) { - in6_dev->cnf.mc_forwarding++; + atomic_inc(&in6_dev->cnf.mc_forwarding); inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF, NETCONFA_MC_FORWARDING, dev->ifindex, &in6_dev->cnf); @@ -1551,7 +1551,7 @@ static int ip6mr_sk_init(struct mr_table *mrt, struct sock *sk) } else { rcu_assign_pointer(mrt->mroute_sk, sk); sock_set_flag(sk, SOCK_RCU_FREE); - net->ipv6.devconf_all->mc_forwarding++; + atomic_inc(&net->ipv6.devconf_all->mc_forwarding); } write_unlock_bh(&mrt_lock);

@@ -1584,7 +1584,7 @@ int ip6mr_sk_done(struct sock *sk) * so the RCU grace period before sk freeing * is guaranteed by sk_destruct() */ - net->ipv6.devconf_all->mc_forwarding--; + atomic_dec(&net->ipv6.devconf_all->mc_forwarding); write_unlock_bh(&mrt_lock); inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, NETCONFA_MC_FORWARDING,