fix: address lock-free bug

Author: kaahos

ddprof-lib/src/main/cpp/threadFilter.h

@@ -215,7 +215,8 @@ class ThreadFilter {
                 snapshot.correlation_id = 0;
             }
             snapshot.generation = blockGeneration();
-            snapshot.active = snapshot.active_state != OSThreadState::UNKNOWN;
+            snapshot.active = snapshot.owner != BlockRunOwner::NONE &&
+                snapshot.active_state != OSThreadState::UNKNOWN;
             snapshot.has_stack_reference =
                 sampled && (snapshot.call_trace_id != 0 || snapshot.correlation_id != 0);
             return snapshot;

ddprof-lib/src/test/cpp/threadFilter_ut.cpp

@@ -701,6 +701,22 @@ TEST_F(ThreadFilterTest, BlockRunSnapshotCapturesFirstCallTraceId) {
     EXPECT_EQ(0ULL, snapshot.correlation_id);
 }
 
+TEST_F(ThreadFilterTest, BlockRunSnapshotTreatsOwnerlessStateAsInactive) {
+    int slot_id = filter->registerThread();
+    ASSERT_GE(slot_id, 0);
+    ThreadFilter::Slot *slot = filter->slotForId(slot_id);
+    ASSERT_NE(nullptr, slot);
+
+    slot->active_block_state.store(OSThreadState::IO_WAIT, std::memory_order_release);
+    slot->active_block_owner.store(static_cast<int>(BlockRunOwner::NONE),
+                                   std::memory_order_release);
+
+    BlockRunSnapshot snapshot = filter->snapshotBlockedRun(slot_id);
+    EXPECT_FALSE(snapshot.active);
+    EXPECT_EQ(BlockRunOwner::NONE, snapshot.owner);
+    EXPECT_EQ(OSThreadState::IO_WAIT, snapshot.active_state);
+}
+
 TEST_F(ThreadFilterTest, BlockRunSnapshotCapturesFirstCorrelationId) {
     int slot_id = filter->registerThread();
     ASSERT_GE(slot_id, 0);