Merge tag 'batadv-net-pullrequest-20220508' of git://git.open-mesh.org/linux-merge

Simon Wunderlich says:

====================
Here is a batman-adv bugfix:

 - Don't skb_split skbuffs with frag_list, by Sven Eckelmann

* tag 'batadv-net-pullrequest-20220508' of git://git.open-mesh.org/linux-merge:
  batman-adv: Don't skb_split skbuffs with frag_list
====================

Link: https://lore.kernel.org/r/20220508132110.20451-1-sw@simonwunderlich.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/batman-adv/fragmentation.c

@@ -475,6 +475,17 @@ int batadv_frag_send_packet(struct sk_buff *skb,
 		goto free_skb;
 	}
 
+	/* GRO might have added fragments to the fragment list instead of
+	 * frags[]. But this is not handled by skb_split and must be
+	 * linearized to avoid incorrect length information after all
+	 * batman-adv fragments were created and submitted to the
+	 * hard-interface
+	 */
+	if (skb_has_frag_list(skb) && __skb_linearize(skb)) {
+		ret = -ENOMEM;
+		goto free_skb;
+	}
+
 	/* Create one header to be copied to all fragments */
 	frag_header.packet_type = BATADV_UNICAST_FRAG;
 	frag_header.version = BATADV_COMPAT_VERSION;