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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Lorenz Bauer <lmb@cloudflare.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 080/165] bpf: Clear skb->tstamp in bpf_redirect when necessary
Date:   Sat, 11 Jan 2020 10:49:59 +0100
Message-Id: <20200111094927.877121253@linuxfoundation.org>
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From: Lorenz Bauer <lmb@cloudflare.com>

[ Upstream commit 5133498f4ad1123a5ffd4c08df6431dab882cc32 ]

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: Sasha Levin <sashal@kernel.org>
---
 net/core/filter.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index 6d0111bfdb4a..2f76461c120d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2055,6 +2055,7 @@ 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);
-- 
2.20.1