diff --git a/wp-admin/includes/class-wp-debug-data.php b/wp-admin/includes/class-wp-debug-data.php
index b20776743e..5f96ffa41c 100644
--- a/wp-admin/includes/class-wp-debug-data.php
+++ b/wp-admin/includes/class-wp-debug-data.php
@@ -317,18 +317,22 @@ class WP_Debug_Data {
 		 * from causing a timeout. The default value is 30 seconds, and some
 		 * hosts do not allow you to read configuration values.
 		 */
-		$max_execution_time = 30;
-
 		if ( function_exists( 'ini_get' ) ) {
 			$max_execution_time = ini_get( 'max_execution_time' );
 		}
 
+		// The max_execution_time defaults to 0 when PHP runs from cli.
+		// We still want to limit it below.
+		if ( empty( $max_execution_time ) ) {
+			$max_execution_time = 30;
+		}
+
 		// Here 20 seconds is a "sensible default" for how long to make the user wait for the directory size calculation.
 		// When testing 20 seconds seem enough in nearly all cases. The remaining edge cases are likely testing or development sites
 		// that have very large number of files, for example `node_modules` in plugins or themes, etc.
 		if ( $max_execution_time > 20 ) {
 			$max_execution_time = 20;
-		} elseif ( $max_execution_time > 2 ) {
+		} elseif ( $max_execution_time > 10 ) {
 			// If the max_execution_time is set to lower than 20 seconds, reduce it a bit to prevent
 			// edge-case timeouts that may happen after the size loop has finished running.
 			$max_execution_time -= 1;
@@ -367,12 +371,14 @@ class WP_Debug_Data {
 			}
 
 			if ( $dir_size === false ) {
-				// Error reading
-				$dir_size   = $inaccessible;
+				// Error reading.
+				$dir_size = $inaccessible;
+				// Stop total size calculation.
 				$size_total = null;
 			} elseif ( $dir_size === null ) {
-				// Timeout
-				$dir_size   = $timeout;
+				// Timeout.
+				$dir_size = $timeout;
+				// Stop total size calculation.
 				$size_total = null;
 			} else {
 				$is_subdir = ( strpos( $size_directories[ $size ]['path'], ABSPATH ) === 0 );
diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 90a3bafbb6..f8d2a66216 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -7014,6 +7014,7 @@ function wp_direct_php_update_button() {
  * a blog has exceeded its allowed upload space.
  *
  * @since MU (3.0.0)
+ * @since 5.2.0 $max_execution_time parameter added.
  *
  * @param string $directory Full path of a directory.
  * @param int    $max_execution_time Maximum time to run before giving up. In seconds.
@@ -7051,6 +7052,7 @@ function get_dirsize( $directory, $max_execution_time = null ) {
  *
  * @since MU (3.0.0)
  * @since 4.3.0 $exclude parameter added.
+ * @since 5.2.0 $max_execution_time parameter added.
  *
  * @param string $directory Full path of a directory.
  * @param string $exclude   Optional. Full path of a subdirectory to exclude from the total.
@@ -7067,13 +7069,13 @@ function recurse_dirsize( $directory, $exclude = null, $max_execution_time = nul
 		return false;
 	}
 
-	if ( ! $max_execution_time ) {
-		// Keep the previous behavior but attempt to prevent fatal errors from timeout.
+	if ( $max_execution_time === null ) {
+		// Keep the previous behavior but attempt to prevent fatal errors from timeout if possible.
 		if ( function_exists( 'ini_get' ) ) {
 			$max_execution_time = ini_get( 'max_execution_time' );
 		} else {
-			// Use PHP default.
-			$max_execution_time = 30;
+			// Disable...
+			$max_execution_time = 0;
 		}
 
 		// Leave 1 second "buffer" for other operations if $max_execution_time has reasonable value.
@@ -7095,7 +7097,7 @@ function recurse_dirsize( $directory, $exclude = null, $max_execution_time = nul
 					}
 				}
 
-				if ( microtime( true ) - WP_START_TIMESTAMP > $max_execution_time ) {
+				if ( $max_execution_time > 0 && microtime( true ) - WP_START_TIMESTAMP > $max_execution_time ) {
 					// Time exceeded. Give up instead of risking a fatal timeout.
 					$size = null;
 					break;
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 41f15c177c..69dbde9a0d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.2-beta1-45110';
+$wp_version = '5.2-beta1-45111';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.