diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-10-10 20:17:43 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-10-13 10:13:08 -0700 |
| commit | d9b55bf7b6788ec0bd1db1acefbc4feb1399144a (patch) | |
| tree | 428615c37202b0d44173735a2efe04651aff469b /net | |
| parent | e0d694d638dba768b47be31c22e1a9b4f862f561 (diff) | |
tcp: annotate tp->urg_seq lockless reads
There two places where we fetch tp->urg_seq while
this field can change from IRQ or other cpu.
We need to add READ_ONCE() annotations, and also make
sure write side use corresponding WRITE_ONCE() to avoid
store-tearing.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp.c | 5 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 2 |
2 files changed, 4 insertions, 3 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 652568750cb1..577a8c6eef9f 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -546,7 +546,7 @@ __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait) (state != TCP_SYN_RECV || rcu_access_pointer(tp->fastopen_rsk))) { int target = sock_rcvlowat(sk, 0, INT_MAX); - if (tp->urg_seq == READ_ONCE(tp->copied_seq) && + if (READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq) && !sock_flag(sk, SOCK_URGINLINE) && tp->urg_data) target++; @@ -607,7 +607,8 @@ int tcp_ioctl(struct sock *sk, int cmd, unsigned long arg) unlock_sock_fast(sk, slow); break; case SIOCATMARK: - answ = tp->urg_data && tp->urg_seq == READ_ONCE(tp->copied_seq); + answ = tp->urg_data && + READ_ONCE(tp->urg_seq) == READ_ONCE(tp->copied_seq); break; case SIOCOUTQ: if (sk->sk_state == TCP_LISTEN) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a30aae3a6a18..16342e043ab3 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5356,7 +5356,7 @@ static void tcp_check_urg(struct sock *sk, const struct tcphdr *th) } tp->urg_data = TCP_URG_NOTYET; - tp->urg_seq = ptr; + WRITE_ONCE(tp->urg_seq, ptr); /* Disable header prediction. */ tp->pred_flags = 0; |