From: Eric Dumazet <edumazet@google.com>
Date: Thu, 7 Jun 2012 22:59:59 +0000 (+0000)
Subject: be2net: fix a race in be_xmit()
X-Git-Tag: firefly_0821_release~7541^2~1008
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9e7d7c544c8a3ec827f72d9af9c2c3efa45e5325;p=firefly-linux-kernel-4.4.55.git

be2net: fix a race in be_xmit()

[ Upstream commit cd8f76c0a0c6fce0b2cf23c9bd0123f91453f46d ]

As soon as hardware is notified of a transmit, we no longer can assume
skb can be dereferenced, as TX completion might have freed the packet.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Sathya Perla <sathya.perla@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/benet/be_main.c b/drivers/net/benet/be_main.c
index a485f7fdaf37..2ce5db5e9c60 100644
--- a/drivers/net/benet/be_main.c
+++ b/drivers/net/benet/be_main.c
@@ -763,6 +763,8 @@ static netdev_tx_t be_xmit(struct sk_buff *skb,
 
 	copied = make_tx_wrbs(adapter, skb, wrb_cnt, dummy_wrb);
 	if (copied) {
+		int gso_segs = skb_shinfo(skb)->gso_segs;
+
 		/* record the sent skb in the sent_skb table */
 		BUG_ON(tx_obj->sent_skb_list[start]);
 		tx_obj->sent_skb_list[start] = skb;
@@ -780,8 +782,7 @@ static netdev_tx_t be_xmit(struct sk_buff *skb,
 
 		be_txq_notify(adapter, txq->id, wrb_cnt);
 
-		be_tx_stats_update(adapter, wrb_cnt, copied,
-				skb_shinfo(skb)->gso_segs, stopped);
+		be_tx_stats_update(adapter, wrb_cnt, copied, gso_segs, stopped);
 	} else {
 		txq->head = start;
 		dev_kfree_skb_any(skb);