tcp: tcp_get_info() should read tcp_time_stamp later

Commit b369e7fd41f7 ("tcp: make TCP_INFO more consistent") moved
lock_sock_fast() earlier in tcp_get_info()

This has the minor effect that jiffies value being sampled at the
beginning of tcp_get_info() is more likely to be off by one, and we
report big tcpi_last_data_sent values (like 0xFFFFFFFF).

Since we lock the socket, fetching tcp_time_stamp right before
doing the jiffies_to_msecs() calls is enough to remove these
wrong values.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index cf4555581282..1e319a525d51 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2770,7 +2770,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
 {
         const struct tcp_sock *tp = tcp_sk(sk); /* iff sk_type == SOCK_STREAM */
         const struct inet_connection_sock *icsk = inet_csk(sk);
-        u32 now = tcp_time_stamp, intv;
+        u32 now, intv;
         u64 rate64;
         bool slow;
         u32 rate;
@@ -2839,6 +2839,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
         info->tcpi_retrans = tp->retrans_out;
         info->tcpi_fackets = tp->fackets_out;
 
+        now = tcp_time_stamp;
         info->tcpi_last_data_sent = jiffies_to_msecs(now - tp->lsndtime);
         info->tcpi_last_data_recv = jiffies_to_msecs(now - icsk->icsk_ack.lrcvtime);
         info->tcpi_last_ack_recv = jiffies_to_msecs(now - tp->rcv_tstamp);