SUNRPC: Fix a race with XPRT_CONNECTING

Trond Myklebust · Trond Myklebust · commit cf76785d3071 · 2018-12-18T11:04:03.000-05:00
Ensure that we clear XPRT_CONNECTING before releasing the XPRT_LOCK so that
we don't have races between the (asynchronous) socket setup code and
tasks in xprt_connect().

Signed-off-by: Trond Myklebust &lt;trond.myklebust@hammerspace.com&gt;
Tested-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
@@ -2090,8 +2090,8 @@ static void xs_udp_setup_socket(struct work_struct *work)
 	trace_rpc_socket_connect(xprt, sock, 0);
 	status = 0;
 out:
-	xprt_unlock_connect(xprt, transport);
 	xprt_clear_connecting(xprt);
+	xprt_unlock_connect(xprt, transport);
 	xprt_wake_pending_tasks(xprt, status);
 }
 
@@ -2327,8 +2327,8 @@ static void xs_tcp_setup_socket(struct work_struct *work)
 	}
 	status = -EAGAIN;
 out:
-	xprt_unlock_connect(xprt, transport);
 	xprt_clear_connecting(xprt);
+	xprt_unlock_connect(xprt, transport);
 	xprt_wake_pending_tasks(xprt, status);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -2090,8 +2090,8 @@ static void xs_udp_setup_socket(struct work_struct *work)`
`2090`	`2090`	`trace_rpc_socket_connect(xprt, sock, 0);`
`2091`	`2091`	`status = 0;`
`2092`	`2092`	`out:`
`2093`		`- xprt_unlock_connect(xprt, transport);`
`2094`	`2093`	`xprt_clear_connecting(xprt);`
	`2094`	`+ xprt_unlock_connect(xprt, transport);`
`2095`	`2095`	`xprt_wake_pending_tasks(xprt, status);`
`2096`	`2096`	`}`
`2097`	`2097`
`@@ -2327,8 +2327,8 @@ static void xs_tcp_setup_socket(struct work_struct *work)`
`2327`	`2327`	`}`
`2328`	`2328`	`status = -EAGAIN;`
`2329`	`2329`	`out:`
`2330`		`- xprt_unlock_connect(xprt, transport);`
`2331`	`2330`	`xprt_clear_connecting(xprt);`
	`2331`	`+ xprt_unlock_connect(xprt, transport);`
`2332`	`2332`	`xprt_wake_pending_tasks(xprt, status);`
`2333`	`2333`	`}`
`2334`	`2334`