[PATCH openEuler-1.0-LTS 051/109] tcp: annotate tp->copied_seq lockless reads

14 Apr 2021

From: Eric Dumazet edumazet@google.com
stable inclusion
from linux-4.19.181
commit 7209e120966c5557106caed20cb4bb08ab26d5d3
--------------------------------
[ 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@google.com
Signed-off-by: David S. Miller davem@davemloft.net
Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
Signed-off-by: Yang Yingliang yangyingliang@huawei.com
Signed-off-by: Cheng Jian cj.chengjian@huawei.com
---
 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 98e8ee8bb759..f639c7d60838 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(&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. */
@@ -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 c9e97f304f98..a96b252c742c 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 c7c3df30d8bc..effba01eed84 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5897,7 +5897,7 @@ 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);
@@ -5972,7 +5972,7 @@ 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
@@ -6134,7 +6134,7 @@ 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 960c3b11fb93..c41e095a63fb 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2431,7 +2431,7 @@ 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 7ba8a90772b0..0b1a04fa5439 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 3cfefec81975..662aa48173b8 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 2e76ebfdc907..de9b9c0bf18f 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 "
-- 
2.25.1

    

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[PATCH openEuler-1.0-LTS 051/109] tcp: annotate tp->copied_seq lockless reads