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Message-ID: <20240229114016.2995906-2-edumazet@google.com>
Date: Thu, 29 Feb 2024 11:40:11 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: Jiri Pirko <jiri@...dia.com>, David Ahern <dsahern@...nel.org>, netdev@...r.kernel.org,
Florian Westphal <fw@...len.de>, eric.dumazet@...il.com, Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 1/6] 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 <edumazet@...gle.com>
---
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 af741af61830aeb695e7e75608515547dade8f39..1316046d5f28955376091d9e02ab4594e19fbd09 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;
--
2.44.0.278.ge034bb2e1d-goog
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