1 files changed, 10 insertions, 6 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 90863307bcd9..b1a17758003a 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1229,7 +1229,7 @@ SCTP_STATIC void sctp_close(struct sock *sk, long timeout)
 
         ep = sctp_sk(sk)->ep;
 
-        /* Walk all associations on a socket, not on an endpoint.  */
+        /* Walk all associations on an endpoint.  */
         list_for_each_safe(pos, temp, &ep->asocs) {
                 asoc = list_entry(pos, struct sctp_association, asocs);
 
@@ -5318,6 +5318,7 @@ static int sctp_wait_for_sndbuf(struct sctp_association *asoc, long *timeo_p,
                  */
                 sctp_release_sock(sk);
                 current_timeo = schedule_timeout(current_timeo);
+                BUG_ON(sk != asoc->base.sk);
                 sctp_lock_sock(sk);
 
                 *timeo_p = current_timeo;
@@ -5605,12 +5606,14 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
          */
         newsp->type = type;
 
-        spin_lock_bh(&oldsk->sk_lock.slock);
-        /* Migrate the backlog from oldsk to newsk. */
-        sctp_backlog_migrate(assoc, oldsk, newsk);
-        /* Migrate the association to the new socket. */
+        /* Mark the new socket "in-use" by the user so that any packets
+         * that may arrive on the association after we've moved it are
+         * queued to the backlog.  This prevents a potential race between
+         * backlog processing on the old socket and new-packet processing
+         * on the new socket.
+         */
+        sctp_lock_sock(newsk);
         sctp_assoc_migrate(assoc, newsk);
-        spin_unlock_bh(&oldsk->sk_lock.slock);
 
         /* If the association on the newsk is already closed before accept()
          * is called, set RCV_SHUTDOWN flag.
@@ -5619,6 +5622,7 @@ static void sctp_sock_migrate(struct sock *oldsk, struct sock *newsk,
                 newsk->sk_shutdown |= RCV_SHUTDOWN;
 
         newsk->sk_state = SCTP_SS_ESTABLISHED;
+        sctp_release_sock(newsk);
 }
 
 /* This proto struct describes the ULP interface for SCTP.  */