From: Tariq Toukan <redacted>
Date: Thu, 31 Jan 2019 15:02:43 +0200

From: Saeed Mahameed <redacted>

When an ethernet frame is padded to meet the minimum ethernet frame
size, the padding octets are not covered by the hardware checksum.
Fortunately the padding octets are usually zero's, which don't affect
checksum. However, it is not guaranteed. For example, switches might
choose to make other use of these octets.
This repeatedly causes kernel hardware checksum fault.

Prior to the cited commit below, skb checksum was forced to be
CHECKSUM_NONE when padding is detected. After it, we need to keep
skb->csum updated. However, fixing up CHECKSUM_COMPLETE requires to
verify and parse IP headers, it does not worth the effort as the packets
are so small that CHECKSUM_COMPLETE has no significant advantage.

Fixes: 88078d98d1bb ("net: pskb_trim_rcsum() and CHECKSUM_COMPLETE are friends")
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Saeed Mahameed <redacted>
Signed-off-by: Tariq Toukan <redacted>
---
 drivers/net/ethernet/mellanox/mlx4/en_rx.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

Hi Dave,
Please queue for -stable >= v4.18.

Please look into Eric's feedback and update the comment as needed.

Thank you.