From: Ryder Lee <ryder.lee@mediatek.com>
Date: Tue, 29 Dec 2020 04:15:30 +0000 (+0800)
Subject: mt76: mt7915: drop zero-length packet to avoid Tx hang
X-Git-Tag: v5.12-rc1~200^2~62^2~16^2~66
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b747fa343817fd322b4463dda99d28fc51e19c52;p=thirdparty%2Fkernel%2Flinux.git

mt76: mt7915: drop zero-length packet to avoid Tx hang

Hardware wouldn't add LLC-SNAP when skb->data_len is 0, which causes
Tx hang, so add a check to drop this kind of packet.

Tested-by: Bo Jiao <bo.jiao@mediatek.com>
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
index dab46bd5d05dc..ecabab77a9136 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mac.c
@@ -942,6 +942,9 @@ int mt7915_tx_prepare_skb(struct mt76_dev *mdev, void *txwi_ptr,
 	int id, i, nbuf = tx_info->nbuf - 1;
 	u8 *txwi = (u8 *)txwi_ptr;
 
+	if (unlikely(tx_info->skb->len <= ETH_HLEN))
+		return -EINVAL;
+
 	if (!wcid)
 		wcid = &dev->mt76.global_wcid;