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Diffstat (limited to 'net/ipv4/tcp_offload.c')
-rw-r--r--net/ipv4/tcp_offload.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 11f69bbf9307..b6a2aa1dcf56 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -149,11 +149,19 @@ struct sk_buff *tcp_gso_segment(struct sk_buff *skb,
* is freed by GSO engine
*/
if (copy_destructor) {
+ int delta;
+
swap(gso_skb->sk, skb->sk);
swap(gso_skb->destructor, skb->destructor);
sum_truesize += skb->truesize;
- refcount_add(sum_truesize - gso_skb->truesize,
- &skb->sk->sk_wmem_alloc);
+ delta = sum_truesize - gso_skb->truesize;
+ /* In some pathological cases, delta can be negative.
+ * We need to either use refcount_add() or refcount_sub_and_test()
+ */
+ if (likely(delta >= 0))
+ refcount_add(delta, &skb->sk->sk_wmem_alloc);
+ else
+ WARN_ON_ONCE(refcount_sub_and_test(-delta, &skb->sk->sk_wmem_alloc));
}
delta = htonl(oldlen + (skb_tail_pointer(skb) -