[Devel] [PATCH 3/3] Make sure we free the struct socket of SOCK_DEAD sockets

[Dan Smith]

Avoid the leak reported by Serge for sockets that don't get attached to
a file.  Do this by orphaning the socket on restore if it is marked as
SOCK_DEAD.  If it is needed later for sending a buffer, temporarily
adopt it for that process.

Signed-off-by: Dan Smith <danms at us.ibm.com>
---
 net/checkpoint.c      |   13 ++++++++++++-
 net/unix/checkpoint.c |   16 ++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletions(-)

diff --git a/net/checkpoint.c b/net/checkpoint.c
index d22341a..0bfca77 100644
--- a/net/checkpoint.c
+++ b/net/checkpoint.c
@@ -627,6 +627,7 @@ struct sock *do_sock_restore(struct ckpt_ctx *ctx)
 {
 	struct ckpt_hdr_socket *h;
 	struct socket *sock;
+	struct sock *sk;
 	int ret;
 
 	h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_SOCKET);
@@ -661,7 +662,14 @@ struct sock *do_sock_restore(struct ckpt_ctx *ctx)
 
 	ckpt_hdr_put(ctx, h);
 
-	return sock->sk;
+	sk = sock->sk;
+	if (sock_flag(sk, SOCK_DEAD)) {
+		sock_orphan(sk);
+		sock->sk = NULL;
+		sock_release(sock);
+	}
+
+	return sk;
  err:
 	ckpt_hdr_put(ctx, h);
 	sock_release(sock);
@@ -688,6 +696,9 @@ struct file *sock_file_restore(struct ckpt_ctx *ctx, struct ckpt_hdr_file *ptr)
 	if (IS_ERR(sk))
 		return ERR_PTR(PTR_ERR(sk));
 
+	/* We should have a struct socket if we were attached to a file */
+	BUG_ON(!sk->sk_socket);
+
 	file = sock_alloc_attach_fd(sk->sk_socket);
 	if (IS_ERR(file))
 		return file;
diff --git a/net/unix/checkpoint.c b/net/unix/checkpoint.c
index 60f6a0c..da2b408 100644
--- a/net/unix/checkpoint.c
+++ b/net/unix/checkpoint.c
@@ -180,6 +180,7 @@ static int sock_read_buffer_sendmsg(struct ckpt_ctx *ctx,
 	struct kvec kvec;
 	struct ckpt_hdr_socket_buffer *h;
 	struct sock *sk;
+	struct socket *sock = NULL;
 	uint8_t sock_shutdown;
 	uint8_t peer_shutdown = 0;
 	void *buf;
@@ -229,6 +230,15 @@ static int sock_read_buffer_sendmsg(struct ckpt_ctx *ctx,
 			ckpt_debug("Failed to join: %i\n", ret);
 			goto out;
 		}
+	} else
+
+	if (!sk->sk_socket) {
+		ret = sock_create(sk->sk_family, sk->sk_type, 0, &sock);
+		if (ret < 0)
+			goto out;
+		if (unix_sk(sk)->peer)
+			sock->state = SS_CONNECTED;
+		sock_graft(sk, sock);
 	}
 
 	kvec.iov_len = len;
@@ -275,6 +285,12 @@ static int sock_read_buffer_sendmsg(struct ckpt_ctx *ctx,
 	ckpt_hdr_put(ctx, h);
 	kfree(buf);
 
+	if (sock) {
+		sock_orphan(sk);
+		sock->sk = NULL;
+		sock_release(sock);
+	}
+
 	return ret;
 }
 
-- 
1.6.2.5

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