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inet: annotate data-races around ifa->ifa_flags
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ifa->ifa_flags 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>
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@davem330
Eric Dumazet authored and davem330 committed Mar 1, 2024
1 parent 9f6fa3c commit 3ddc223
Showing 1 changed file with 13 additions and 9 deletions.
22 changes: 13 additions & 9 deletions net/ipv4/devinet.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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)) {
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;

Expand Down Expand Up @@ -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,
Expand Down

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