net: Fix skb_copy_expand() handling of ->csum_start

It should only be adjusted if ip_summed == CHECKSUM_PARTIAL.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index c699159b3ede..ce88293a34e2 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -932,7 +932,8 @@ struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
         copy_skb_header(n, skb);
 
         off                  = newheadroom - oldheadroom;
-        n->csum_start       += off;
+        if (n->ip_summed == CHECKSUM_PARTIAL)
+                n->csum_start += off;
 #ifdef NET_SKBUFF_DATA_USES_OFFSET
         n->transport_header += off;
         n->network_header   += off;