inet: annotate data-races around ifa->ifa_valid_lft

ifa->ifa_valid_lft can be read locklessly.

Add appropriate READ_ONCE()/WRITE_ONCE() annotations.

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

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 1316046d5f28955376091d9e02ab4594e19fbd09..99f3e7c57d36ff028edadd4efd66d996ddc5d9b4 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -714,26 +714,26 @@ static void check_lifetime(struct work_struct *work)
                rcu_read_lock();
                hlist_for_each_entry_rcu(ifa, &inet_addr_lst[i], hash) {
                        unsigned long age, tstamp;
+                       u32 valid_lft;
 
                        if (ifa->ifa_flags & IFA_F_PERMANENT)
                                continue;
 
+                       valid_lft = READ_ONCE(ifa->ifa_valid_lft);
                        tstamp = READ_ONCE(ifa->ifa_tstamp);
                        /* We try to batch several events at once. */
                        age = (now - tstamp +
                               ADDRCONF_TIMER_FUZZ_MINUS) / HZ;
 
-                       if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME &&
-                           age >= ifa->ifa_valid_lft) {
+                       if (valid_lft != INFINITY_LIFE_TIME &&
+                           age >= valid_lft) {
                                change_needed = true;
                        } else if (ifa->ifa_preferred_lft ==
                                   INFINITY_LIFE_TIME) {
                                continue;
                        } else if (age >= ifa->ifa_preferred_lft) {
-                               if (time_before(tstamp +
-                                               ifa->ifa_valid_lft * HZ, next))
-                                       next = tstamp +
-                                              ifa->ifa_valid_lft * HZ;
+                               if (time_before(tstamp + valid_lft * HZ, next))
+                                       next = tstamp + valid_lft * HZ;
 
                                if (!(ifa->ifa_flags & IFA_F_DEPRECATED))
                                        change_needed = true;
@@ -810,7 +810,7 @@ static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft,
 
        timeout = addrconf_timeout_fixup(valid_lft, HZ);
        if (addrconf_finite_timeout(timeout))
-               ifa->ifa_valid_lft = timeout;
+               WRITE_ONCE(ifa->ifa_valid_lft, timeout);
        else
                ifa->ifa_flags |= IFA_F_PERMANENT;
 
@@ -1699,7 +1699,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
        tstamp = READ_ONCE(ifa->ifa_tstamp);
        if (!(ifm->ifa_flags & IFA_F_PERMANENT)) {
                preferred = ifa->ifa_preferred_lft;
-               valid = ifa->ifa_valid_lft;
+               valid = READ_ONCE(ifa->ifa_valid_lft);
                if (preferred != INFINITY_LIFE_TIME) {
                        long tval = (jiffies - tstamp) / HZ;