[PATCH v2 net] qede: validate non LSO skb length

Although it is unlikely that stack could transmit a non LSO
skb with length > MTU, however in some cases or environment such
occurrences actually resulted into firmware asserts due to packet
length being greater than the max supported by the device (~9700B).

This patch adds the safeguard for such odd cases to avoid firmware
asserts.

v1->v2:
--------

* Added "Fixes" tag with one of the initial driver commit
  which enabled the TX traffic actually (as this was probably
  day1 issue which was discovered recently by some customer
  environment)

Fixes: a2ec6172d29c ("qede: Add support for link")
Signed-off-by: Manish Chopra <manishc@marvell.com>
Signed-off-by: Alok Prasad <redacted>
Signed-off-by: Prabhakar Kushwaha <redacted>
Signed-off-by: Ariel Elior <redacted>
---
 drivers/net/ethernet/qlogic/qede/qede_fp.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c
index 065e900..999abcf 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_fp.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c

@@ -1643,6 +1643,13 @@ netdev_tx_t qede_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 			data_split = true;
 		}
 	} else {
+		if (unlikely(skb->len > ETH_TX_MAX_NON_LSO_PKT_LEN)) {
+			DP_ERR(edev, "Unexpected non LSO skb length = 0x%x\n", skb->len);
+			qede_free_failed_tx_pkt(txq, first_bd, 0, false);
+			qede_update_tx_producer(txq);
+			return NETDEV_TX_OK;
+		}
+
 		val |= ((skb->len & ETH_TX_DATA_1ST_BD_PKT_LEN_MASK) <<
 			 ETH_TX_DATA_1ST_BD_PKT_LEN_SHIFT);
 	}
--

1.8.3.1

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski [off-list ref]:

On Fri, 3 Dec 2021 09:44:13 -0800 you wrote:

Although it is unlikely that stack could transmit a non LSO
skb with length > MTU, however in some cases or environment such
occurrences actually resulted into firmware asserts due to packet
length being greater than the max supported by the device (~9700B).

This patch adds the safeguard for such odd cases to avoid firmware
asserts.

[...]

Here is the summary with links:
  - [v2,net] qede: validate non LSO skb length
    https://git.kernel.org/netdev/net/c/8e227b198a55

You are awesome, thank you!
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