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authorEric Dumazet <eric.dumazet@gmail.com>2009-12-03 16:06:13 -0800
committerDavid S. Miller <davem@davemloft.net>2009-12-03 16:06:13 -0800
commit49d09007879ce7bee36ab453c73e97c00adce884 (patch)
tree6b6a28e0fd8befd4bad5fb1474ce4e0dea9ed6dd
parent3320eae51d6e4c65b4733bf4d87de3b833973a1f (diff)
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tcp: diag: Dont report negative values for rx queue
Both netlink and /proc/net/tcp interfaces can report transient negative values for rx queue. ss -> State Recv-Q Send-Q Local Address:Port Peer Address:Port ESTAB -6 6 127.0.0.1:45956 127.0.0.1:3333 netstat -> tcp 4294967290 6 127.0.0.1:37784 127.0.0.1:3333 ESTABLISHED This is because we dont lock socket while computing tp->rcv_nxt - tp->copied_seq, and another CPU can update copied_seq before rcv_next in RX path. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/tcp_diag.c2
-rw-r--r--net/ipv4/tcp_ipv4.c12
2 files changed, 11 insertions, 3 deletions
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index fcbcd4f..939edb3 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -27,7 +27,7 @@ static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
r->idiag_rqueue = sk->sk_ack_backlog;
r->idiag_wqueue = sk->sk_max_ack_backlog;
} else {
- r->idiag_rqueue = tp->rcv_nxt - tp->copied_seq;
+ r->idiag_rqueue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
r->idiag_wqueue = tp->write_seq - tp->snd_una;
}
if (info != NULL)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index fee9aab..29002ab 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2318,6 +2318,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
__be32 src = inet->inet_rcv_saddr;
__u16 destp = ntohs(inet->inet_dport);
__u16 srcp = ntohs(inet->inet_sport);
+ int rx_queue;
if (icsk->icsk_pending == ICSK_TIME_RETRANS) {
timer_active = 1;
@@ -2333,12 +2334,19 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
timer_expires = jiffies;
}
+ if (sk->sk_state == TCP_LISTEN)
+ rx_queue = sk->sk_ack_backlog;
+ else
+ /*
+ * because we dont lock socket, we might find a transient negative value
+ */
+ rx_queue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);
+
seq_printf(f, "%4d: %08X:%04X %08X:%04X %02X %08X:%08X %02X:%08lX "
"%08X %5d %8d %lu %d %p %lu %lu %u %u %d%n",
i, src, srcp, dest, destp, sk->sk_state,
tp->write_seq - tp->snd_una,
- sk->sk_state == TCP_LISTEN ? sk->sk_ack_backlog :
- (tp->rcv_nxt - tp->copied_seq),
+ rx_queue,
timer_active,
jiffies_to_clock_t(timer_expires - jiffies),
icsk->icsk_retransmits,