[PATCH 5.10 60/66] SUNRPC: Dont call connect() more than once on a TCP socket

Greg Kroah-Hartman
2022-05-16T19:55:38Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

commit 89f42494f92f448747bd8a7ab1ae8b5d5520577d upstream.

Avoid socket state races due to repeated calls to ->connect() using the
same socket. If connect() returns 0 due to the connection having
completed, but we are in fact in a closing state, then we may leave the
XPRT_CONNECTING flag set on the transport.

Reported-by: Enrico Scholz <enrico.scholz@sigma-chemnitz.de>
Fixes: 3be232f11a3c ("SUNRPC: Prevent immediate close+reconnect")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
[meenashanmugam: Backported to 5.10: Fixed merge conflict in xs_tcp_setup_socket]
Signed-off-by: Meena Shanmugam <meenashanmugam@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/sunrpc/xprtsock.h | 1 +
net/sunrpc/xprtsock.c | 21 +++++++++++----------
2 files changed, 12 insertions(+), 10 deletions(-)

--- a/include/linux/sunrpc/xprtsock.h
+++ b/include/linux/sunrpc/xprtsock.h
@@ -89,5 +89,6 @@ struct sock_xprt {
#define XPRT_SOCK_WAKE_WRITE (5)
#define XPRT_SOCK_WAKE_PENDING (6)
#define XPRT_SOCK_WAKE_DISCONNECT (7)
+#define XPRT_SOCK_CONNECT_SENT (8)

#endif /* _LINUX_SUNRPC_XPRTSOCK_H */
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2260,10 +2260,14 @@ static void xs_tcp_setup_socket(struct w
struct rpc_xprt *xprt = &transport->xprt;
int status = -EIO;

- if (!sock) {
- sock = xs_create_sock(xprt, transport,
- xs_addr(xprt)->sa_family, SOCK_STREAM,
- IPPROTO_TCP, true);
+ if (xprt_connected(xprt))
+ goto out;
+ if (test_and_clear_bit(XPRT_SOCK_CONNECT_SENT,
+ &transport->sock_state) ||
+ !sock) {
+ xs_reset_transport(transport);
+ sock = xs_create_sock(xprt, transport, xs_addr(xprt)->sa_family,
+ SOCK_STREAM, IPPROTO_TCP, true);
if (IS_ERR(sock)) {
status = PTR_ERR(sock);
goto out;
@@ -2294,6 +2298,7 @@ static void xs_tcp_setup_socket(struct w
break;
case 0:
case -EINPROGRESS:
+ set_bit(XPRT_SOCK_CONNECT_SENT, &transport->sock_state);
case -EALREADY:
xprt_unlock_connect(xprt, transport);
return;
@@ -2345,13 +2350,9 @@ static void xs_connect(struct rpc_xprt *

WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));

- if (transport->sock != NULL && !xprt_connecting(xprt)) {
+ if (transport->sock != NULL) {
dprintk("RPC: xs_connect delayed xprt %p for %lu "
- "seconds\n",
- xprt, xprt->reestablish_timeout / HZ);
-
- /* Start by resetting any existing state */
- xs_reset_transport(transport);
+ "seconds\n", xprt, xprt->reestablish_timeout / HZ);

delay = xprt_reconnect_delay(xprt);
xprt_reconnect_backoff(xprt, XS_TCP_INIT_REEST_TO);