From 2ff4623c95bc6c3a8a229629669772a181a3979c Mon Sep 17 00:00:00 2001
From: Filip Leonarski <filip.leonarski@psi.ch>
Date: Thu, 16 Apr 2026 09:01:27 +0200
Subject: [PATCH] PreviewCounter: Fix locking

---
 preview/PreviewCounter.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/preview/PreviewCounter.cpp b/preview/PreviewCounter.cpp
index 56cd1540..9b880dd9 100644
--- a/preview/PreviewCounter.cpp
+++ b/preview/PreviewCounter.cpp
@@ -33,5 +33,6 @@ PreviewCounter &PreviewCounter::Period(const std::optional<std::chrono::microsec
 }
 
 std::optional<std::chrono::microseconds> PreviewCounter::GetPeriod() const {
+    std::unique_lock ul(m);
     return period;
 }