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, 5 insertions, 5 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index ccc5e83cae5d..1c246a4f491e 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -111,7 +111,7 @@ static void svc_release_skb(struct svc_rqst *rqstp)
                 rqstp->rq_xprt_ctxt = NULL;
 
                 dprintk("svc: service %p, releasing skb %p\n", rqstp, skb);
-                skb_free_datagram(svsk->sk_sk, skb);
+                skb_free_datagram_locked(svsk->sk_sk, skb);
         }
 }
 
@@ -578,7 +578,7 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
                                 "svc: received unknown control message %d/%d; "
                                 "dropping RPC reply datagram\n",
                                         cmh->cmsg_level, cmh->cmsg_type);
-                skb_free_datagram(svsk->sk_sk, skb);
+                skb_free_datagram_locked(svsk->sk_sk, skb);
                 return 0;
         }
 
@@ -588,18 +588,18 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
                 if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb)) {
                         local_bh_enable();
                         /* checksum error */
-                        skb_free_datagram(svsk->sk_sk, skb);
+                        skb_free_datagram_locked(svsk->sk_sk, skb);
                         return 0;
                 }
                 local_bh_enable();
-                skb_free_datagram(svsk->sk_sk, skb);
+                skb_free_datagram_locked(svsk->sk_sk, skb);
         } else {
                 /* we can use it in-place */
                 rqstp->rq_arg.head[0].iov_base = skb->data +
                         sizeof(struct udphdr);
                 rqstp->rq_arg.head[0].iov_len = len;
                 if (skb_checksum_complete(skb)) {
-                        skb_free_datagram(svsk->sk_sk, skb);
+                        skb_free_datagram_locked(svsk->sk_sk, skb);
                         return 0;
                 }
                 rqstp->rq_xprt_ctxt = skb;