[PATCH 5.6 08/29] udp: initialize is_flist with 0 in udp_gro_receive

[Greg Kroah-Hartman]

From: Xin Long <lucien.xin@xxxxxxxxx>

[ Upstream commit bde1b56f898ca8112912d7b36e55e1543b3be0cf ]

Without NAPI_GRO_CB(skb)->is_flist initialized, when the dev doesn't
support NETIF_F_GRO_FRAGLIST, is_flist can still be set and fraglist
will be used in udp_gro_receive().

So fix it by initializing is_flist with 0 in udp_gro_receive.

Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.")
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv4/udp_offload.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -453,6 +453,7 @@ struct sk_buff *udp_gro_receive(struct l
 	unsigned int off = skb_gro_offset(skb);
 	int flush = 1;
 
+	NAPI_GRO_CB(skb)->is_flist = 0;
 	if (skb->dev->features & NETIF_F_GRO_FRAGLIST)
 		NAPI_GRO_CB(skb)->is_flist = sk ? !udp_sk(sk)->gro_enabled: 1;