From 531f5d1e4fcbc3e3f1801b272935affbed0acd90 Mon Sep 17 00:00:00 2001
From: Simon L <szaimen@e.mail.de>
Date: Fri, 3 Nov 2023 11:47:12 +0100
Subject: [PATCH] fix semaphore guarding

Signed-off-by: Simon L <szaimen@e.mail.de>
---
 lib/private/Preview/Generator.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/private/Preview/Generator.php b/lib/private/Preview/Generator.php
index 4a1270fa4a6..d936f1d65ad 100644
--- a/lib/private/Preview/Generator.php
+++ b/lib/private/Preview/Generator.php
@@ -244,7 +244,7 @@ class Generator {
 	 * @return bool
 	 */
 	public static function unguardWithSemaphore($semId): bool {
-		if (!is_resource($semId) || !extension_loaded('sysvsem')) {
+		if ($semId === false || get_class($semId) !== 'SysvSemaphore' || !extension_loaded('sysvsem')) {
 			return false;
 		}
 		return sem_release($semId);
-- 
2.39.5