diff --git a/src/Storages/StorageTinyLog.cpp b/src/Storages/StorageTinyLog.cpp
index 6ce41dac614..b63a0c7d255 100644
--- a/src/Storages/StorageTinyLog.cpp
+++ b/src/Storages/StorageTinyLog.cpp
@@ -358,6 +358,9 @@ void TinyLogBlockOutputStream::writeSuffix()
         storage.file_checker.update(file);
     storage.file_checker.save();
 
+    /// unlock should be done from the same thread as lock, and dtor may be
+    /// called from different thread, so it should be done here (at least in
+    /// case of no exceptions occurred)
     lock.unlock();
 }
 
diff --git a/tests/queries/0_stateless/01795_TinyLog_rwlock_ub.reference b/tests/queries/0_stateless/01795_TinyLog_rwlock_ub.reference
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/queries/0_stateless/01795_TinyLog_rwlock_ub.sql b/tests/queries/0_stateless/01795_TinyLog_rwlock_ub.sql
new file mode 100644
index 00000000000..7afa2b7e164
--- /dev/null
+++ b/tests/queries/0_stateless/01795_TinyLog_rwlock_ub.sql
@@ -0,0 +1,5 @@
+DROP TABLE IF EXISTS underlying_01795;
+CREATE TABLE underlying_01795 (key UInt64) Engine=TinyLog();
+INSERT INTO FUNCTION remote('127.1', currentDatabase(), underlying_01795) SELECT toUInt64(number) FROM system.numbers LIMIT 1;
+SELECT * FROM underlying_01795 FORMAT Null;
+DROP TABLE underlying_01795;