ethernet: myri10ge: Fix a use after free in myri10ge_sw_tso

In myri10ge_sw_tso, the skb_list_walk_safe macro will set
(curr) = (segs) and (next) = (curr)->next. If status!=0 is true,
the memory pointed by curr and segs will be free by dev_kfree_skb_any(curr).
But later, the segs is used by segs = segs->next and causes a uaf.

As (next) = (curr)->next, my patch replaces seg->next to next.

Fixes: 536577f3 ("net: myri10ge: use skb_list_walk_safe helper for gso segments")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/myricom/myri10ge/myri10ge.c

@@ -2897,7 +2897,7 @@ static netdev_tx_t myri10ge_sw_tso(struct sk_buff *skb,
 			dev_kfree_skb_any(curr);
 			if (segs != NULL) {
 				curr = segs;
-				segs = segs->next;
+				segs = next;
 				curr->next = NULL;
 				dev_kfree_skb_any(segs);
 			}