release/5.2.35/bpf-Clear-skb-tstamp-in-bpf_redirect-when-necessary.patch

From 6140aa059245f37877171b62a372c412f33c4ba2 Mon Sep 17 00:00:00 2001
From: Lorenz Bauer <lmb@cloudflare.com>
Date: Fri, 13 Dec 2019 18:08:17 +0000
Subject: [PATCH] bpf: Clear skb->tstamp in bpf_redirect when necessary

commit 5133498f4ad1123a5ffd4c08df6431dab882cc32 upstream.

Redirecting a packet from ingress to egress by using bpf_redirect
breaks if the egress interface has an fq qdisc installed. This is the same
problem as fixed in 'commit 8203e2d844d3 ("net: clear skb->tstamp in forwarding paths")

Clear skb->tstamp when redirecting into the egress path.

Fixes: 80b14dee2bea ("net: Add a new socket option for a future transmit time.")
Fixes: fb420d5d91c1 ("tcp/fq: move back to CLOCK_MONOTONIC")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20191213180817.2510-1-lmb@cloudflare.com
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/core/filter.c b/net/core/filter.c
index 82e0af0f221b..7acc2bd95f39 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2054,6 +2054,7 @@ static inline int __bpf_tx_skb(struct net_device *dev, struct sk_buff *skb)
 	}
 
 	skb->dev = dev;
+	skb->tstamp = 0;
 
 	dev_xmit_recursion_inc();
 	ret = dev_queue_xmit(skb);
-- 
2.7.4