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authorEric Dumazet <edumazet@google.com>2019-10-11 06:17:40 +0300
committerDavid S. Miller <davem@davemloft.net>2019-10-13 20:13:08 +0300
commit7db48e983930285b765743ebd665aecf9850582b (patch)
tree3ee9dad33e8d9a0d27cc576a5f3ebf077f5af2d0 /net/ipv4
parentdba7d9b8c739df27ff3a234c81d6c6b23e3986fa (diff)
downloadlinux-7db48e983930285b765743ebd665aecf9850582b.tar.xz
tcp: annotate tp->copied_seq lockless reads
There are few places where we fetch tp->copied_seq while this field can change from IRQ or other cpu. We need to add READ_ONCE() annotations, and also make sure write sides use corresponding WRITE_ONCE() to avoid store-tearing. Note that tcp_inq_hint() was already using READ_ONCE(tp->copied_seq) Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
-rw-r--r--net/ipv4/tcp.c20
-rw-r--r--net/ipv4/tcp_diag.c3
-rw-r--r--net/ipv4/tcp_input.c6
-rw-r--r--net/ipv4/tcp_ipv4.c2
-rw-r--r--net/ipv4/tcp_minisocks.c2
-rw-r--r--net/ipv4/tcp_output.c2
6 files changed, 18 insertions, 17 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 883ee863db43..c322ad071e17 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -477,7 +477,7 @@ static void tcp_tx_timestamp(struct sock *sk, u16 tsflags)
static inline bool tcp_stream_is_readable(const struct tcp_sock *tp,
int target, struct sock *sk)
{
- return (READ_ONCE(tp->rcv_nxt) - tp->copied_seq >= target) ||
+ return (READ_ONCE(tp->rcv_nxt) - READ_ONCE(tp->copied_seq) >= target) ||
(sk->sk_prot->stream_memory_read ?
sk->sk_prot->stream_memory_read(sk) : false);
}
@@ -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 == tp->copied_seq &&
+ if (tp->urg_seq == READ_ONCE(tp->copied_seq) &&
!sock_flag(sk, SOCK_URGINLINE) &&
tp->urg_data)
target++;
@@ -607,7 +607,7 @@ 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 == tp->copied_seq;
+ answ = tp->urg_data && tp->urg_seq == READ_ONCE(tp->copied_seq);
break;
case SIOCOUTQ:
if (sk->sk_state == TCP_LISTEN)
@@ -1668,9 +1668,9 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
sk_eat_skb(sk, skb);
if (!desc->count)
break;
- tp->copied_seq = seq;
+ WRITE_ONCE(tp->copied_seq, seq);
}
- tp->copied_seq = seq;
+ WRITE_ONCE(tp->copied_seq, seq);
tcp_rcv_space_adjust(sk);
@@ -1819,7 +1819,7 @@ static int tcp_zerocopy_receive(struct sock *sk,
out:
up_read(&current->mm->mmap_sem);
if (length) {
- tp->copied_seq = seq;
+ WRITE_ONCE(tp->copied_seq, seq);
tcp_rcv_space_adjust(sk);
/* Clean up data we have read: This will do ACK frames. */
@@ -2117,7 +2117,7 @@ found_ok_skb:
if (urg_offset < used) {
if (!urg_offset) {
if (!sock_flag(sk, SOCK_URGINLINE)) {
- ++*seq;
+ WRITE_ONCE(*seq, *seq + 1);
urg_hole++;
offset++;
used--;
@@ -2139,7 +2139,7 @@ found_ok_skb:
}
}
- *seq += used;
+ WRITE_ONCE(*seq, *seq + used);
copied += used;
len -= used;
@@ -2166,7 +2166,7 @@ skip_copy:
found_fin_ok:
/* Process the FIN. */
- ++*seq;
+ WRITE_ONCE(*seq, *seq + 1);
if (!(flags & MSG_PEEK))
sk_eat_skb(sk, skb);
break;
@@ -2588,7 +2588,7 @@ int tcp_disconnect(struct sock *sk, int flags)
__kfree_skb(sk->sk_rx_skb_cache);
sk->sk_rx_skb_cache = NULL;
}
- tp->copied_seq = tp->rcv_nxt;
+ WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
tp->urg_data = 0;
tcp_write_queue_purge(sk);
tcp_fastopen_active_disable_ofo_check(sk);
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index cd219161f106..66273c8a55c2 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -26,7 +26,8 @@ static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
} else if (sk->sk_type == SOCK_STREAM) {
const struct tcp_sock *tp = tcp_sk(sk);
- r->idiag_rqueue = max_t(int, READ_ONCE(tp->rcv_nxt) - tp->copied_seq, 0);
+ r->idiag_rqueue = max_t(int, READ_ONCE(tp->rcv_nxt) -
+ READ_ONCE(tp->copied_seq), 0);
r->idiag_wqueue = tp->write_seq - tp->snd_una;
}
if (info)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 5b7c8768ed5f..a30aae3a6a18 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5961,7 +5961,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
/* Remember, tcp_poll() does not lock socket!
* Change state from SYN-SENT only after copied_seq
* is initialized. */
- tp->copied_seq = tp->rcv_nxt;
+ WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
smc_check_reset_syn(tp);
@@ -6036,7 +6036,7 @@ discard:
}
WRITE_ONCE(tp->rcv_nxt, TCP_SKB_CB(skb)->seq + 1);
- tp->copied_seq = tp->rcv_nxt;
+ WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
tp->rcv_wup = TCP_SKB_CB(skb)->seq + 1;
/* RFC1323: The window in SYN & SYN/ACK segments is
@@ -6216,7 +6216,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
tcp_try_undo_spurious_syn(sk);
tp->retrans_stamp = 0;
tcp_init_transfer(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB);
- tp->copied_seq = tp->rcv_nxt;
+ WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
}
smp_mb();
tcp_set_state(sk, TCP_ESTABLISHED);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 5089dd6bee0f..39560f482e0b 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2456,7 +2456,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
* we might find a transient negative value.
*/
rx_queue = max_t(int, READ_ONCE(tp->rcv_nxt) -
- tp->copied_seq, 0);
+ READ_ONCE(tp->copied_seq), 0);
seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
"%08X %5u %8d %lu %d %pK %lu %lu %u %u %d",
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index adc6ce486a38..c4731d26ab4a 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -478,7 +478,7 @@ struct sock *tcp_create_openreq_child(const struct sock *sk,
seq = treq->rcv_isn + 1;
newtp->rcv_wup = seq;
- newtp->copied_seq = seq;
+ WRITE_ONCE(newtp->copied_seq, seq);
WRITE_ONCE(newtp->rcv_nxt, seq);
newtp->segs_in = 1;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 84ae4d1449ea..7dda12720169 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3433,7 +3433,7 @@ static void tcp_connect_init(struct sock *sk)
else
tp->rcv_tstamp = tcp_jiffies32;
tp->rcv_wup = tp->rcv_nxt;
- tp->copied_seq = tp->rcv_nxt;
+ WRITE_ONCE(tp->copied_seq, tp->rcv_nxt);
inet_csk(sk)->icsk_rto = tcp_timeout_init(sk);
inet_csk(sk)->icsk_retransmits = 0;