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, 1 insertions, 3 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d0d436d6216..0fa9f70e4b1 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -999,9 +999,7 @@ try_again:
                 err = ulen;
 
 out_free:
-        lock_sock(sk);
-        skb_free_datagram(sk, skb);
-        release_sock(sk);
+        skb_free_datagram_locked(sk, skb);
 out:
         return err;