tcp: avoid oops in tcp_metrics and reset tcpm_stamp

	In tcp_tw_remember_stamp we incorrectly checked tw
instead of tm, it can lead to oops if the cached entry is
not found.

	tcpm_stamp was not updated in tcpm_check_stamp when
tcpm_suck_dst was called, move the update into tcpm_suck_dst,
so that we do not call it infinitely on every next cache hit
after TCP_METRICS_TIMEOUT.

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
index 992f1bff4fc6..2288a6399e1e 100644
--- a/net/ipv4/tcp_metrics.c
+++ b/net/ipv4/tcp_metrics.c
@@ -107,6 +107,8 @@ static void tcpm_suck_dst(struct tcp_metrics_block *tm, struct dst_entry *dst)
 {
         u32 val;
 
+        tm->tcpm_stamp = jiffies;
+
         val = 0;
         if (dst_metric_locked(dst, RTAX_RTT))
                 val |= 1 << TCP_METRIC_RTT;
@@ -158,7 +160,6 @@ static struct tcp_metrics_block *tcpm_new(struct dst_entry *dst,
                         goto out_unlock;
         }
         tm->tcpm_addr = *addr;
-        tm->tcpm_stamp = jiffies;
 
         tcpm_suck_dst(tm, dst);
 
@@ -621,7 +622,7 @@ bool tcp_tw_remember_stamp(struct inet_timewait_sock *tw)
 
         rcu_read_lock();
         tm = __tcp_get_metrics_tw(tw);
-        if (tw) {
+        if (tm) {
                 const struct tcp_timewait_sock *tcptw;
                 struct sock *sk = (struct sock *) tw;