tcp: warn on negative reordering values

From: Soheil Hassas Yeganeh <[email protected]>

Commit bafbb9c73241 ("tcp: eliminate negative reordering in tcp_clean_rtx_queue") fixes an issue for negative reordering metrics.

To be resilient to such errors, warn and return when a negative metric is passed to tcp_update_reordering().

---
 net/ipv4/tcp_input.c | 3 +++
 1 file changed, 3 insertions(+)

index f27dff64e59e..eb5eb87060a2 100644
@@ -886,6 +886,9 @@ static void tcp_update_reordering(struct sock *sk, const int metric,
 	struct tcp_sock *tp = tcp_sk(sk);
 	int mib_idx;
 
+	if (WARN_ON_ONCE(metric < 0))
+		return;
+
 	if (metric > tp->reordering) {
 		tp->reordering = min(sysctl_tcp_max_reordering, metric);
 

2.13.0.303.g4ebf302169-goog

From: Soheil Hassas Yeganeh <[email protected]>
Date: Tue, 16 May 2017 17:39:02 -0400

Applied, thanks.