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Message-ID: <20240229114016.2995906-5-edumazet@google.com>
Date: Thu, 29 Feb 2024 11:40:14 +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 4/6] inet: annotate data-races around ifa->ifa_flags
ifa->ifa_flags can be read locklessly.
Add appropriate READ_ONCE()/WRITE_ONCE() annotations.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
net/ipv4/devinet.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 368fb56e1f1b2e3b7888f611a3f113f3bd5fc2af..550b775cbbf3c140c66e224c69996df7051b3d36 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -716,8 +716,10 @@ static void check_lifetime(struct work_struct *work)
unsigned long age, tstamp;
u32 preferred_lft;
u32 valid_lft;
+ u32 flags;
- if (ifa->ifa_flags & IFA_F_PERMANENT)
+ flags = READ_ONCE(ifa->ifa_flags);
+ if (flags & IFA_F_PERMANENT)
continue;
preferred_lft = READ_ONCE(ifa->ifa_preferred_lft);
@@ -737,7 +739,7 @@ static void check_lifetime(struct work_struct *work)
if (time_before(tstamp + valid_lft * HZ, next))
next = tstamp + valid_lft * HZ;
- if (!(ifa->ifa_flags & IFA_F_DEPRECATED))
+ if (!(flags & IFA_F_DEPRECATED))
change_needed = true;
} else if (time_before(tstamp + preferred_lft * HZ,
next)) {
@@ -805,21 +807,23 @@ static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft,
__u32 prefered_lft)
{
unsigned long timeout;
+ u32 flags;
- ifa->ifa_flags &= ~(IFA_F_PERMANENT | IFA_F_DEPRECATED);
+ flags = ifa->ifa_flags & ~(IFA_F_PERMANENT | IFA_F_DEPRECATED);
timeout = addrconf_timeout_fixup(valid_lft, HZ);
if (addrconf_finite_timeout(timeout))
WRITE_ONCE(ifa->ifa_valid_lft, timeout);
else
- ifa->ifa_flags |= IFA_F_PERMANENT;
+ flags |= IFA_F_PERMANENT;
timeout = addrconf_timeout_fixup(prefered_lft, HZ);
if (addrconf_finite_timeout(timeout)) {
if (timeout == 0)
- ifa->ifa_flags |= IFA_F_DEPRECATED;
+ flags |= IFA_F_DEPRECATED;
WRITE_ONCE(ifa->ifa_preferred_lft, timeout);
}
+ WRITE_ONCE(ifa->ifa_flags, flags);
WRITE_ONCE(ifa->ifa_tstamp, jiffies);
if (!ifa->ifa_cstamp)
WRITE_ONCE(ifa->ifa_cstamp, ifa->ifa_tstamp);
@@ -1313,7 +1317,7 @@ static __be32 in_dev_select_addr(const struct in_device *in_dev,
const struct in_ifaddr *ifa;
in_dev_for_each_ifa_rcu(ifa, in_dev) {
- if (ifa->ifa_flags & IFA_F_SECONDARY)
+ if (READ_ONCE(ifa->ifa_flags) & IFA_F_SECONDARY)
continue;
if (ifa->ifa_scope != RT_SCOPE_LINK &&
ifa->ifa_scope <= scope)
@@ -1341,7 +1345,7 @@ __be32 inet_select_addr(const struct net_device *dev, __be32 dst, int scope)
localnet_scope = RT_SCOPE_LINK;
in_dev_for_each_ifa_rcu(ifa, in_dev) {
- if (ifa->ifa_flags & IFA_F_SECONDARY)
+ if (READ_ONCE(ifa->ifa_flags) & IFA_F_SECONDARY)
continue;
if (min(ifa->ifa_scope, localnet_scope) > scope)
continue;
@@ -1688,7 +1692,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
ifm = nlmsg_data(nlh);
ifm->ifa_family = AF_INET;
ifm->ifa_prefixlen = ifa->ifa_prefixlen;
- ifm->ifa_flags = ifa->ifa_flags;
+ ifm->ifa_flags = READ_ONCE(ifa->ifa_flags);
ifm->ifa_scope = ifa->ifa_scope;
ifm->ifa_index = ifa->ifa_dev->dev->ifindex;
@@ -1728,7 +1732,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa,
nla_put_string(skb, IFA_LABEL, ifa->ifa_label)) ||
(ifa->ifa_proto &&
nla_put_u8(skb, IFA_PROTO, ifa->ifa_proto)) ||
- nla_put_u32(skb, IFA_FLAGS, ifa->ifa_flags) ||
+ nla_put_u32(skb, IFA_FLAGS, ifm->ifa_flags) ||
(ifa->ifa_rt_priority &&
nla_put_u32(skb, IFA_RT_PRIORITY, ifa->ifa_rt_priority)) ||
put_cacheinfo(skb, READ_ONCE(ifa->ifa_cstamp), tstamp,
--
2.44.0.278.ge034bb2e1d-goog
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