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>

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 9e949403c13635cf83e1de83ab32d2d946e40bfd..c965400fb93405b4a371dcfef3d629412e105002 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -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);

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index b8378814532cead0275e8b7a656f78450993f619..1ba97933c74fbd12e21f273f0aeda2313bd608b7 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -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;
        }

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 31b86fe661aa6cd94fb5d8848900406c2db110e3..0559bd0005858631f88c706f98c625ad0bfff278 100644 (file)
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -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;