| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 251/312] net: bcmgenet: fix skb_len in bcmgenet_xmit_single() | Date | Fri, 8 May 2020 14:34:02 +0200 |
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From: Petri Gynther <pgynther@google.com>
commit 7dd399130efb5a454daf24075b7563d197114e39 upstream.
skb_len needs to be skb_headlen(skb) in bcmgenet_xmit_single().
Fragmented skbs can have only Ethernet + IP + TCP headers (14+20+20=54 bytes) in the linear buffer, followed by the rest in fragments. Bumping skb_len to ETH_ZLEN would be incorrect for this case, as it would introduce garbage between TCP header and the fragment data.
This also works with regular/non-fragmented small packets < ETH_ZLEN bytes. Successfully tested this on GENETv3 with 42-byte ARP frames.
For testing, I used: ethtool -K eth0 tx-checksum-ipv4 off ethtool -K eth0 tx-checksum-ipv6 off echo 0 > /proc/sys/net/ipv4/tcp_timestamps
Fixes: 1c1008c793fa ("net: bcmgenet: add main driver file") Signed-off-by: Petri Gynther <pgynther@google.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/net/ethernet/broadcom/genet/bcmgenet.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c @@ -1346,7 +1346,7 @@ static int bcmgenet_xmit_single(struct n tx_cb_ptr->skb = skb; - skb_len = skb_headlen(skb) < ETH_ZLEN ? ETH_ZLEN : skb_headlen(skb); + skb_len = skb_headlen(skb); mapping = dma_map_single(kdev, skb->data, skb_len, DMA_TO_DEVICE); ret = dma_mapping_error(kdev, mapping);
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