check: More verbose messages when sock diag infratructure is missing.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-check.c

@@ -88,11 +88,14 @@ static int check_sock_diag(void)
 {
 	int ret;
 
-	ret = collect_sockets(getpid());
+	ret = collect_sockets(0);
 	if (!ret)
 		return 0;
 
-	pr_msg("sock diag infrastructure is incomplete.\n");
+	pr_msg("The sock diag infrastructure is incomplete.\n");
+	pr_msg("Make sure you have:\n");
+	pr_msg(" 1. *_DIAG kernel config options turned on;\n");
+	pr_msg(" 2. *_diag.ko modules loaded (if compiled as modules).\n");
 	return -1;
 }
 

sockets.c

@@ -530,7 +530,7 @@ out:
 	if (rst >= 0) {
 		if (restore_ns(rst, &net_ns_desc) < 0)
 			err = -1;
-	} else {
+	} else if (pid != 0) {
 		/*
 		 * If netns isn't dumped, crtools will fail only
 		 * if an unsupported socket will be really dumped.