From: Alexander Lobakin alobakin@pm.me
[ Upstream commit 4b1a86281cc1d0de46df3ad2cb8c1f86ac07681c ]
UDP GRO uses udp_hdr(skb) in its .gro_receive() callback. While it's probably OK for non-frag0 paths (when all headers or even the entire frame are already in skb head), this inline points to junk when using Fast GRO (napi_gro_frags() or napi_gro_receive() with only Ethernet header in skb head and all the rest in the frags) and breaks GRO packet compilation and the packet flow itself. To support both modes, skb_gro_header_fast() + skb_gro_header_slow() are typically used. UDP even has an inline helper that makes use of them, udp_gro_udphdr(). Use that instead of troublemaking udp_hdr() to get rid of the out-of-order delivers.
Present since the introduction of plain UDP GRO in 5.0-rc1.
Fixes: e20cf8d3f1f7 ("udp: implement GRO for plain UDP sockets.") Cc: Eric Dumazet edumazet@google.com Signed-off-by: Alexander Lobakin alobakin@pm.me Acked-by: Willem de Bruijn willemb@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/udp_offload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -366,7 +366,7 @@ out: static struct sk_buff *udp_gro_receive_segment(struct list_head *head, struct sk_buff *skb) { - struct udphdr *uh = udp_hdr(skb); + struct udphdr *uh = udp_gro_udphdr(skb); struct sk_buff *pp = NULL; struct udphdr *uh2; struct sk_buff *p;