From 3cd3e72ccb3aade0e8fe037ef07a44b341ab577c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 29 Feb 2024 11:40:11 +0000 Subject: [PATCH] inet: annotate data-races around ifa->ifa_tstamp and ifa->ifa_cstamp ifa->ifa_tstamp can be read locklessly. Add appropriate READ_ONCE()/WRITE_ONCE() annotations. Do the same for ifa->ifa_cstamp to prepare upcoming changes. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/devinet.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index af741af61830..1316046d5f28 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -713,13 +713,14 @@ 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; + unsigned long age, tstamp; if (ifa->ifa_flags & IFA_F_PERMANENT) continue; + tstamp = READ_ONCE(ifa->ifa_tstamp); /* We try to batch several events at once. */ - age = (now - ifa->ifa_tstamp + + age = (now - tstamp + ADDRCONF_TIMER_FUZZ_MINUS) / HZ; if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME && @@ -729,17 +730,17 @@ static void check_lifetime(struct work_struct *work) INFINITY_LIFE_TIME) { continue; } else if (age >= ifa->ifa_preferred_lft) { - if (time_before(ifa->ifa_tstamp + + if (time_before(tstamp + ifa->ifa_valid_lft * HZ, next)) - next = ifa->ifa_tstamp + + next = tstamp + ifa->ifa_valid_lft * HZ; if (!(ifa->ifa_flags & IFA_F_DEPRECATED)) change_needed = true; - } else if (time_before(ifa->ifa_tstamp + + } else if (time_before(tstamp + ifa->ifa_preferred_lft * HZ, next)) { - next = ifa->ifa_tstamp + + next = tstamp + ifa->ifa_preferred_lft * HZ; } } @@ -819,9 +820,9 @@ static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft, ifa->ifa_flags |= IFA_F_DEPRECATED; ifa->ifa_preferred_lft = timeout; } - ifa->ifa_tstamp = jiffies; + WRITE_ONCE(ifa->ifa_tstamp, jiffies); if (!ifa->ifa_cstamp) - ifa->ifa_cstamp = ifa->ifa_tstamp; + WRITE_ONCE(ifa->ifa_cstamp, ifa->ifa_tstamp); } static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh, @@ -1676,6 +1677,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa, { struct ifaddrmsg *ifm; struct nlmsghdr *nlh; + unsigned long tstamp; u32 preferred, valid; nlh = nlmsg_put(skb, args->portid, args->seq, args->event, sizeof(*ifm), @@ -1694,11 +1696,12 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa, nla_put_s32(skb, IFA_TARGET_NETNSID, args->netnsid)) goto nla_put_failure; + tstamp = READ_ONCE(ifa->ifa_tstamp); if (!(ifm->ifa_flags & IFA_F_PERMANENT)) { preferred = ifa->ifa_preferred_lft; valid = ifa->ifa_valid_lft; if (preferred != INFINITY_LIFE_TIME) { - long tval = (jiffies - ifa->ifa_tstamp) / HZ; + long tval = (jiffies - tstamp) / HZ; if (preferred > tval) preferred -= tval; @@ -1728,7 +1731,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa, nla_put_u32(skb, IFA_FLAGS, ifa->ifa_flags) || (ifa->ifa_rt_priority && nla_put_u32(skb, IFA_RT_PRIORITY, ifa->ifa_rt_priority)) || - put_cacheinfo(skb, ifa->ifa_cstamp, ifa->ifa_tstamp, + put_cacheinfo(skb, READ_ONCE(ifa->ifa_cstamp), tstamp, preferred, valid)) goto nla_put_failure;