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 f00432063db1a0db484e85193eccc6845435b80e Mon Sep 17 00:00:00 2001 From: Trond Myklebust trond.myklebust@hammerspace.com Date: Sun, 3 Apr 2022 15:58:11 -0400 Subject: [PATCH] SUNRPC: Ensure we flush any closed sockets before xs_xprt_free()

We must ensure that all sockets are closed before we call xprt_free() and release the reference to the net namespace. The problem is that calling fput() will defer closing the socket until delayed_fput() gets called. Let's fix the situation by allowing rpciod and the transport teardown code (which runs on the system wq) to call __fput_sync(), and directly close the socket.

Reported-by: Felix Fu foyjog@gmail.com Acked-by: Al Viro viro@zeniv.linux.org.uk Fixes: a73881c96d73 ("SUNRPC: Fix an Oops in udp_poll()") Cc: stable@vger.kernel.org # 5.1.x: 3be232f11a3c: SUNRPC: Prevent immediate close+reconnect Cc: stable@vger.kernel.org # 5.1.x: 89f42494f92f: SUNRPC: Don't call connect() more than once on a TCP socket Cc: stable@vger.kernel.org # 5.1.x Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com

diff --git a/fs/file_table.c b/fs/file_table.c index 7d2e692b66a9..ada8fe814db9 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -412,6 +412,7 @@ void __fput_sync(struct file *file) }

EXPORT_SYMBOL(fput); +EXPORT_SYMBOL(__fput_sync);

void __init files_init(void) { diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h index ac33892da411..a4848c7bab80 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -1004,7 +1004,6 @@ DEFINE_RPC_XPRT_LIFETIME_EVENT(connect); DEFINE_RPC_XPRT_LIFETIME_EVENT(disconnect_auto); DEFINE_RPC_XPRT_LIFETIME_EVENT(disconnect_done); DEFINE_RPC_XPRT_LIFETIME_EVENT(disconnect_force); -DEFINE_RPC_XPRT_LIFETIME_EVENT(disconnect_cleanup); DEFINE_RPC_XPRT_LIFETIME_EVENT(destroy);

DECLARE_EVENT_CLASS(rpc_xprt_event, diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 73344ffb2692..ad62eba540a4 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -930,12 +930,7 @@ void xprt_connect(struct rpc_task *task) if (!xprt_lock_write(xprt, task)) return;

- if (test_and_clear_bit(XPRT_CLOSE_WAIT, &xprt->state)) { - trace_xprt_disconnect_cleanup(xprt); - xprt->ops->close(xprt); - } - - if (!xprt_connected(xprt)) { + if (!xprt_connected(xprt) && !test_bit(XPRT_CLOSE_WAIT, &xprt->state)) { task->tk_rqstp->rq_connect_cookie = xprt->connect_cookie; rpc_sleep_on_timeout(&xprt->pending, task, NULL, xprt_request_timeout(task->tk_rqstp)); diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 9b75891b3cc0..c6a13893e308 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -879,7 +879,7 @@ static int xs_local_send_request(struct rpc_rqst *req)

/* Close the stream if the previous transmission was incomplete */ if (xs_send_request_was_aborted(transport, req)) { - xs_close(xprt); + xprt_force_disconnect(xprt); return -ENOTCONN; }

@@ -915,7 +915,7 @@ static int xs_local_send_request(struct rpc_rqst *req) -status); fallthrough; case -EPIPE: - xs_close(xprt); + xprt_force_disconnect(xprt); status = -ENOTCONN; }

@@ -1185,6 +1185,16 @@ static void xs_reset_transport(struct sock_xprt *transport)

if (sk == NULL) return; + /* + * Make sure we're calling this in a context from which it is safe + * to call __fput_sync(). In practice that means rpciod and the + * system workqueue. + */ + if (!(current->flags & PF_WQ_WORKER)) { + WARN_ON_ONCE(1); + set_bit(XPRT_CLOSE_WAIT, &xprt->state); + return; + }

if (atomic_read(&transport->xprt.swapper)) sk_clear_memalloc(sk); @@ -1208,7 +1218,7 @@ static void xs_reset_transport(struct sock_xprt *transport) mutex_unlock(&transport->recv_mutex);

trace_rpc_socket_close(xprt, sock); - fput(filp); + __fput_sync(filp);

xprt_disconnect_done(xprt); }