diff --git a/libtransmission/torrent.cc b/libtransmission/torrent.cc
index 4c034edf3..a41de0b6e 100644
--- a/libtransmission/torrent.cc
+++ b/libtransmission/torrent.cc
@@ -1522,6 +1522,7 @@ tr_stat const* tr_torrentStat(tr_torrent* tor)
     using namespace stat_helpers;
 
     TR_ASSERT(tr_isTorrent(tor));
+    auto const lock = tor->unique_lock();
 
     auto const now = tr_time_msec();
     auto const now_sec = tr_time();