Here is a totally untested patch that tries to trivially process
these new frags + frag_list skbs.  It should actually be trivial
to make this generate TSO packets by just adding a gso_ok check
and short-circuit.

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 3735fad..ec8e8bc 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c

@@ -2816,7 +2816,24 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
 			hsize = len;
 
 		if (!hsize && i >= nfrags) {
-			BUG_ON(fskb->len != len);
+			if (fskb->len != len) {
+				SKB_FRAG_ASSERT(fskb);
+
+				nskb = skb_segment(fskb, features);
+
+				err = PTR_ERR(nskb);
+				if (IS_ERR(nskb))
+					goto err;
+				err = -ENOMEM;
+
+				if (segs)
+					tail->next = nskb;
+				else
+					segs = nskb;
+				tail = nskb;
+				while (tail->next)
+					tail = tail->next;
+			}
 
 			pos += len;
 			nskb = skb_clone(fskb, GFP_ATOMIC);

Thanks,