net: fix sk_forward_alloc corruption

On UDP sockets, we must call skb_free_datagram() with socket locked,
or risk sk_forward_alloc corruption. This requirement is not respected
in SUNRPC.

Add a convenient helper, skb_free_datagram_locked() and use it in SUNRPC

Reported-by: Francis Moreau <francis.moro@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6aebfceca3eb..bcdd6606f468 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1757,6 +1757,8 @@ extern int	       skb_copy_datagram_const_iovec(const struct sk_buff *from,
                                                      int to_offset,
                                                      int size);
 extern void            skb_free_datagram(struct sock *sk, struct sk_buff *skb);
+extern void            skb_free_datagram_locked(struct sock *sk,
+                                                struct sk_buff *skb);
 extern int             skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
                                          unsigned int flags);
 extern __wsum          skb_checksum(const struct sk_buff *skb, int offset,