diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-11-05 14:11:51 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-12-31 16:45:03 +0100 |
| commit | 074b5c1221953ff1e8b101831f847cab32e32fe9 (patch) | |
| tree | 8053d70c621d8c504a10351639f89d6c646e815b /include | |
| parent | ba4c792cae769d2db21d8cc0ff78bf23b6a672c6 (diff) | |
net: avoid potential false sharing in neighbor related code
[ Upstream commit 25c7a6d1f90e208ec27ca854b1381ed39842ec57 ]
There are common instances of the following construct :
if (n->confirmed != now)
n->confirmed = now;
A C compiler could legally remove the conditional.
Use READ_ONCE()/WRITE_ONCE() to avoid this problem.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/arp.h | 4 | ||||
| -rw-r--r-- | include/net/ndisc.h | 8 | ||||
| -rw-r--r-- | include/net/sock.h | 12 |
3 files changed, 12 insertions, 12 deletions
diff --git a/include/net/arp.h b/include/net/arp.h index c8f580a0e6b1..4950191f6b2b 100644 --- a/include/net/arp.h +++ b/include/net/arp.h @@ -57,8 +57,8 @@ static inline void __ipv4_confirm_neigh(struct net_device *dev, u32 key) unsigned long now = jiffies; /* avoid dirtying neighbour */ - if (n->confirmed != now) - n->confirmed = now; + if (READ_ONCE(n->confirmed) != now) + WRITE_ONCE(n->confirmed, now); } rcu_read_unlock_bh(); } diff --git a/include/net/ndisc.h b/include/net/ndisc.h index b2f715ca0567..b5ebeb3b0de0 100644 --- a/include/net/ndisc.h +++ b/include/net/ndisc.h @@ -414,8 +414,8 @@ static inline void __ipv6_confirm_neigh(struct net_device *dev, unsigned long now = jiffies; /* avoid dirtying neighbour */ - if (n->confirmed != now) - n->confirmed = now; + if (READ_ONCE(n->confirmed) != now) + WRITE_ONCE(n->confirmed, now); } rcu_read_unlock_bh(); } @@ -431,8 +431,8 @@ static inline void __ipv6_confirm_neigh_stub(struct net_device *dev, unsigned long now = jiffies; /* avoid dirtying neighbour */ - if (n->confirmed != now) - n->confirmed = now; + if (READ_ONCE(n->confirmed) != now) + WRITE_ONCE(n->confirmed, now); } rcu_read_unlock_bh(); } diff --git a/include/net/sock.h b/include/net/sock.h index 718e62fbe869..013396e50b91 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1940,8 +1940,8 @@ struct dst_entry *sk_dst_check(struct sock *sk, u32 cookie); static inline void sk_dst_confirm(struct sock *sk) { - if (!sk->sk_dst_pending_confirm) - sk->sk_dst_pending_confirm = 1; + if (!READ_ONCE(sk->sk_dst_pending_confirm)) + WRITE_ONCE(sk->sk_dst_pending_confirm, 1); } static inline void sock_confirm_neigh(struct sk_buff *skb, struct neighbour *n) @@ -1951,10 +1951,10 @@ static inline void sock_confirm_neigh(struct sk_buff *skb, struct neighbour *n) unsigned long now = jiffies; /* avoid dirtying neighbour */ - if (n->confirmed != now) - n->confirmed = now; - if (sk && sk->sk_dst_pending_confirm) - sk->sk_dst_pending_confirm = 0; + if (READ_ONCE(n->confirmed) != now) + WRITE_ONCE(n->confirmed, now); + if (sk && READ_ONCE(sk->sk_dst_pending_confirm)) + WRITE_ONCE(sk->sk_dst_pending_confirm, 0); } } |