diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index b27ac95217..63673b16df 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -174,12 +174,15 @@ PQcommMethods *PqCommMethods = &PqCommSocketMethods;
 void
 pq_init(void)
 {
+	/* initialize state variables */
 	PqSendBufferSize = PQ_SEND_BUFFER_SIZE;
 	PqSendBuffer = MemoryContextAlloc(TopMemoryContext, PqSendBufferSize);
 	PqSendPointer = PqSendStart = PqRecvPointer = PqRecvLength = 0;
 	PqCommBusy = false;
 	PqCommReadingMsg = false;
 	DoingCopyOut = false;
+
+	/* set up process-exit hook to close the socket */
 	on_proc_exit(socket_close, 0);
 
 	/*
@@ -285,28 +288,6 @@ socket_close(int code, Datum arg)
  */
 
 
-/* StreamDoUnlink()
- * Shutdown routine for backend connection
- * If any Unix sockets are used for communication, explicitly close them.
- */
-#ifdef HAVE_UNIX_SOCKETS
-static void
-StreamDoUnlink(int code, Datum arg)
-{
-	ListCell   *l;
-
-	/* Loop through all created sockets... */
-	foreach(l, sock_paths)
-	{
-		char	   *sock_path = (char *) lfirst(l);
-
-		unlink(sock_path);
-	}
-	/* Since we're about to exit, no need to reclaim storage */
-	sock_paths = NIL;
-}
-#endif   /* HAVE_UNIX_SOCKETS */
-
 /*
  * StreamServerPort -- open a "listening" port to accept connections.
  *
@@ -588,16 +569,11 @@ Lock_AF_UNIX(char *unixSocketDir, char *unixSocketPath)
 	 * Once we have the interlock, we can safely delete any pre-existing
 	 * socket file to avoid failure at bind() time.
 	 */
-	unlink(unixSocketPath);
+	(void) unlink(unixSocketPath);
 
 	/*
-	 * Arrange to unlink the socket file(s) at proc_exit.  If this is the
-	 * first one, set up the on_proc_exit function to do it; then add this
-	 * socket file to the list of files to unlink.
+	 * Remember socket file pathnames for later maintenance.
 	 */
-	if (sock_paths == NIL)
-		on_proc_exit(StreamDoUnlink, 0);
-
 	sock_paths = lappend(sock_paths, pstrdup(unixSocketPath));
 
 	return STATUS_OK;
@@ -858,6 +834,26 @@ TouchSocketFiles(void)
 	}
 }
 
+/*
+ * RemoveSocketFiles -- unlink socket files at postmaster shutdown
+ */
+void
+RemoveSocketFiles(void)
+{
+	ListCell   *l;
+
+	/* Loop through all created sockets... */
+	foreach(l, sock_paths)
+	{
+		char	   *sock_path = (char *) lfirst(l);
+
+		/* Ignore any error. */
+		(void) unlink(sock_path);
+	}
+	/* Since we're about to exit, no need to reclaim storage */
+	sock_paths = NIL;
+}
+
 
 /* --------------------------------
  * Low-level I/O routines begin here.
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index 1bb3138a03..000524dcb9 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -370,6 +370,7 @@ static DNSServiceRef bonjour_sdref = NULL;
 /*
  * postmaster.c - function prototypes
  */
+static void CloseServerPorts(int status, Datum arg);
 static void unlink_external_pid_file(int status, Datum arg);
 static void getInstallationPaths(const char *argv0);
 static void checkDataDir(void);
@@ -900,6 +901,11 @@ PostmasterMain(int argc, char *argv[])
 	 * interlock (thanks to whoever decided to put socket files in /tmp :-().
 	 * For the same reason, it's best to grab the TCP socket(s) before the
 	 * Unix socket(s).
+	 *
+	 * Also note that this internally sets up the on_proc_exit function that
+	 * is responsible for removing both data directory and socket lockfiles;
+	 * so it must happen before opening sockets so that at exit, the socket
+	 * lockfiles go away after CloseServerPorts runs.
 	 */
 	CreateDataDirLockFile(true);
 
@@ -924,10 +930,15 @@ PostmasterMain(int argc, char *argv[])
 
 	/*
 	 * Establish input sockets.
+	 *
+	 * First, mark them all closed, and set up an on_proc_exit function that's
+	 * charged with closing the sockets again at postmaster shutdown.
 	 */
 	for (i = 0; i < MAXLISTEN; i++)
 		ListenSocket[i] = PGINVALID_SOCKET;
 
+	on_proc_exit(CloseServerPorts, 0);
+
 	if (ListenAddresses)
 	{
 		char	   *rawstring;
@@ -1271,6 +1282,42 @@ PostmasterMain(int argc, char *argv[])
 }
 
 
+/*
+ * on_proc_exit callback to close server's listen sockets
+ */
+static void
+CloseServerPorts(int status, Datum arg)
+{
+	int			i;
+
+	/*
+	 * First, explicitly close all the socket FDs.  We used to just let this
+	 * happen implicitly at postmaster exit, but it's better to close them
+	 * before we remove the postmaster.pid lockfile; otherwise there's a race
+	 * condition if a new postmaster wants to re-use the TCP port number.
+	 */
+	for (i = 0; i < MAXLISTEN; i++)
+	{
+		if (ListenSocket[i] != PGINVALID_SOCKET)
+		{
+			StreamClose(ListenSocket[i]);
+			ListenSocket[i] = PGINVALID_SOCKET;
+		}
+	}
+
+	/*
+	 * Next, remove any filesystem entries for Unix sockets.  To avoid race
+	 * conditions against incoming postmasters, this must happen after closing
+	 * the sockets and before removing lock files.
+	 */
+	RemoveSocketFiles();
+
+	/*
+	 * We don't do anything about socket lock files here; those will be
+	 * removed in a later on_proc_exit callback.
+	 */
+}
+
 /*
  * on_proc_exit callback to delete external_pid_file
  */
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index ac3e764e8b..5bf595c9e5 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -1018,7 +1018,11 @@ CreateLockFile(const char *filename, bool amPostmaster,
 	if (lock_files == NIL)
 		on_proc_exit(UnlinkLockFiles, 0);
 
-	lock_files = lappend(lock_files, pstrdup(filename));
+	/*
+	 * Use lcons so that the lock files are unlinked in reverse order of
+	 * creation; this is critical!
+	 */
+	lock_files = lcons(pstrdup(filename), lock_files);
 }
 
 /*
diff --git a/src/include/libpq/libpq.h b/src/include/libpq/libpq.h
index c408e5b551..efb2dacbba 100644
--- a/src/include/libpq/libpq.h
+++ b/src/include/libpq/libpq.h
@@ -59,6 +59,7 @@ extern int StreamServerPort(int family, char *hostName,
 extern int	StreamConnection(pgsocket server_fd, Port *port);
 extern void StreamClose(pgsocket sock);
 extern void TouchSocketFiles(void);
+extern void RemoveSocketFiles(void);
 extern void pq_init(void);
 extern int	pq_getbytes(char *s, size_t len);
 extern int	pq_getstring(StringInfo s);