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Message-Id: <20210312083323.3720479-1-eric.dumazet@gmail.com>
Date: Fri, 12 Mar 2021 00:33:21 -0800
From: Eric Dumazet <eric.dumazet@...il.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: "David S . Miller" <davem@...emloft.net>,
netdev <netdev@...r.kernel.org>,
Eric Dumazet <edumazet@...gle.com>,
Eric Dumazet <eric.dumazet@...il.com>, stable@...r.kernel.org
Subject: [PATCH 4.19-stable 1/3] tcp: annotate tp->copied_seq lockless reads
From: Eric Dumazet <edumazet@...gle.com>
[ Upstream commit 7db48e983930285b765743ebd665aecf9850582b ]
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@...gle.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
---
net/ipv4/tcp.c | 18 +++++++++---------
net/ipv4/tcp_diag.c | 3 ++-
net/ipv4/tcp_input.c | 6 +++---
net/ipv4/tcp_ipv4.c | 2 +-
net/ipv4/tcp_minisocks.c | 2 +-
net/ipv4/tcp_output.c | 2 +-
net/ipv6/tcp_ipv6.c | 2 +-
7 files changed, 18 insertions(+), 17 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 98e8ee8bb7593a30442c2e8d9694424c818840ed..f639c7d6083821c8725f5e28312eff3cbfa82e54 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -567,7 +567,7 @@ __poll_t tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
(state != TCP_SYN_RECV || 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++;
@@ -628,7 +628,7 @@ 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)
@@ -1696,9 +1696,9 @@ 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);
@@ -1835,7 +1835,7 @@ static int tcp_zerocopy_receive(struct sock *sk,
out:
up_read(¤t->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. */
@@ -2112,7 +2112,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
if (urg_offset < used) {
if (!urg_offset) {
if (!sock_flag(sk, SOCK_URGINLINE)) {
- ++*seq;
+ WRITE_ONCE(*seq, *seq + 1);
urg_hole++;
offset++;
used--;
@@ -2134,7 +2134,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
}
}
- *seq += used;
+ WRITE_ONCE(*seq, *seq + used);
copied += used;
len -= used;
@@ -2163,7 +2163,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
found_fin_ok:
/* Process the FIN. */
- ++*seq;
+ WRITE_ONCE(*seq, *seq + 1);
if (!(flags & MSG_PEEK))
sk_eat_skb(sk, skb);
break;
@@ -2578,7 +2578,7 @@ int tcp_disconnect(struct sock *sk, int flags)
tcp_clear_xmit_timers(sk);
__skb_queue_purge(&sk->sk_receive_queue);
- 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 c9e97f304f984b9339a683c45dea85a84ccba5bf..a96b252c742cb58108123a5ccad15511634dcfc5 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -30,7 +30,8 @@ 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 5ffc85c8952a04905af7e560ce83135e73980bd3..36bff9291530b19539936609f001a6674acc8f72 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5889,7 +5889,7 @@ 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);
@@ -5964,7 +5964,7 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
}
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
@@ -6126,7 +6126,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb)
tcp_rearm_rto(sk);
} else {
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 7536f4c0bbf4f4b9ff60be4e4c83bca71945382b..627b5fb1eac8ecf808ea33d2994198b4551f3fc9 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2340,7 +2340,7 @@ 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 7ba8a90772b0a631e9d6af29699f99039fbce705..0b1a04fa54392fdb3325d45fd1d5e0aaa3170b6c 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -470,7 +470,7 @@ 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 3cfefec819758989c225b131d845ad1e76552ea7..662aa48173b8197e006127e4d84fb2c1961836a4 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3381,7 +3381,7 @@ 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;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 2e76ebfdc907dde33475310b42fac7fd56eee3a8..de9b9c0bf18f721f44d7ee0e4eec74c0b5576947 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1839,7 +1839,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, 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(seq,
"%4d: %08X%08X%08X%08X:%04X %08X%08X%08X%08X:%04X "
--
2.31.0.rc2.261.g7f71774620-goog
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