From 60e9a8fc836dc60ca5038890f3a0fa646ee2450b Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Wed, 27 May 2026 08:06:29 +0300
Subject: fix(flamegraph): lock metric field reads in AddRecord (1p)

---
 internal/flamegraph/livetrie.go      |  5 ++-
 internal/flamegraph/livetrie_test.go | 66 ++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+), 1 deletion(-)

(limited to 'internal/flamegraph')

diff --git a/internal/flamegraph/livetrie.go b/internal/flamegraph/livetrie.go
index a510a72..47299e6 100644
--- a/internal/flamegraph/livetrie.go
+++ b/internal/flamegraph/livetrie.go
@@ -102,19 +102,22 @@ func (lt *LiveTrie) Ingest(ep *event.Pair) {
 
 // AddRecord adds one already-decoded flamegraph record into the live trie.
 func (lt *LiveTrie) AddRecord(record IterRecord) {
+	lt.mu.Lock()
+
 	value, err := record.Cnt.ValueByName(lt.countField)
 	if err != nil {
+		lt.mu.Unlock()
 		return
 	}
 	heightValue := uint64(0)
 	if lt.heightField != "" {
 		heightValue, err = record.Cnt.ValueByName(lt.heightField)
 		if err != nil {
+			lt.mu.Unlock()
 			return
 		}
 	}
 
-	lt.mu.Lock()
 	frames := lt.buildFrames(record)
 	lt.addLocked(frames, value, heightValue)
 	lt.version.Add(1)
diff --git a/internal/flamegraph/livetrie_test.go b/internal/flamegraph/livetrie_test.go
index a12f5d9..fc9e6a6 100644
--- a/internal/flamegraph/livetrie_test.go
+++ b/internal/flamegraph/livetrie_test.go
@@ -521,6 +521,72 @@ func TestLiveTrieConcurrentIngestAndSnapshot(t *testing.T) {
 	}
 }
 
+func TestLiveTrieConcurrentAddRecordAndMetricToggle(t *testing.T) {
+	lt := NewLiveTrie([]string{"comm", "pid"}, "count", "count")
+
+	const iterations = 1500
+	errCh := make(chan error, 2)
+	var wg sync.WaitGroup
+	wg.Add(3)
+
+	go func() {
+		defer wg.Done()
+		for i := 0; i < iterations; i++ {
+			lt.AddRecord(IterRecord{
+				Comm:    "svc",
+				Pid:     42,
+				TraceID: types.SYS_ENTER_READ,
+				Cnt: Counter{
+					Count:          1,
+					Bytes:          2,
+					Duration:       3,
+					DurationToPrev: 4,
+				},
+			})
+		}
+	}()
+
+	go func() {
+		defer wg.Done()
+		for i := 0; i < iterations; i++ {
+			field := "count"
+			if i%2 == 1 {
+				field = "bytes"
+			}
+			if err := lt.SetCountField(field); err != nil {
+				errCh <- fmt.Errorf("set count field %q: %w", field, err)
+				return
+			}
+		}
+	}()
+
+	go func() {
+		defer wg.Done()
+		for i := 0; i < iterations; i++ {
+			field := "count"
+			if i%2 == 1 {
+				field = "bytes"
+			}
+			if err := lt.SetHeightField(field); err != nil {
+				errCh <- fmt.Errorf("set height field %q: %w", field, err)
+				return
+			}
+		}
+	}()
+
+	wg.Wait()
+	close(errCh)
+	for err := range errCh {
+		t.Fatal(err)
+	}
+
+	payload, _ := lt.SnapshotJSON()
+	var snap SnapshotNode
+	if err := json.Unmarshal(payload, &snap); err != nil {
+		t.Fatalf("unmarshal snapshot after concurrent updates: %v", err)
+	}
+}
+
 func TestLiveTrieStressHighRateConcurrentSnapshot(t *testing.T) {
 	if os.Getenv("IOR_STRESS_TEST") != "1" {
 		t.Skip("set IOR_STRESS_TEST=1 to run stress test")
-- 
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