The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 89f42494f92f448747bd8a7ab1ae8b5d5520577d Mon Sep 17 00:00:00 2001 From: Trond Myklebust trond.myklebust@hammerspace.com Date: Wed, 16 Mar 2022 19:10:43 -0400 Subject: [PATCH] SUNRPC: Don't call connect() more than once on a TCP socket
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
diff --git a/include/linux/sunrpc/xprtsock.h b/include/linux/sunrpc/xprtsock.h index 8c2a712cb242..689062afdd61 100644 --- 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 */ diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 7e39f87cde2d..8f8a03c3315a 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -2235,10 +2235,15 @@ static void xs_tcp_setup_socket(struct work_struct *work)
if (atomic_read(&xprt->swapper)) current->flags |= PF_MEMALLOC; - 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)) { xprt_wake_pending_tasks(xprt, PTR_ERR(sock)); goto out; @@ -2262,6 +2267,7 @@ static void xs_tcp_setup_socket(struct work_struct *work) fallthrough; case -EINPROGRESS: /* SYN_SENT! */ + set_bit(XPRT_SOCK_CONNECT_SENT, &transport->sock_state); if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO) xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO; fallthrough; @@ -2323,13 +2329,9 @@ static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
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);