Merge pull request #97919 from cockroachdb/blathers/backport-release-…

…22.2-97897 release-22.2: tracing: fix stack gathering null bytes bug
cockroachdb · Mar 27, 2023 · fc7ffbb · fc7ffbb
2 parents 1b606cd + f08c037
commit fc7ffbb
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diff --git a/pkg/util/tracing/tracer_snapshots.go b/pkg/util/tracing/tracer_snapshots.go
@@ -161,6 +161,7 @@ func (t *Tracer) generateSnapshot() SpansSnapshot {
 		stacks = make([]byte, n)
 		nbytes := runtime.Stack(stacks, true /* all */)
 		if nbytes < len(stacks) {
+			stacks = stacks[:nbytes]
 			break
 		}
 	}

diff --git a/pkg/util/tracing/tracer_test.go b/pkg/util/tracing/tracer_test.go
@@ -878,3 +878,22 @@ func TestTracerClusterSettings(t *testing.T) {
 	require.False(t, sp.IsNoop())
 	sp.Finish()
 }
+
+func TestTracerSnapshots(t *testing.T) {
+	tr := NewTracer()
+
+	s1 := tr.SaveSnapshot()
+	require.Equal(t, SnapshotID(1), s1.ID)
+	_ = tr.SaveSnapshot()
+	s3 := tr.SaveSnapshot()
+	require.Equal(t, SnapshotID(3), s3.ID)
+	require.Equal(t, 3, len(tr.GetSnapshots()))
+
+	for _, i := range []SnapshotID{2, 1, 3} {
+		s, err := tr.GetSnapshot(i)
+		require.NoError(t, err)
+		for _, s := range s.Stacks {
+			require.Less(t, len(s), 5<<10, s)
+		}
+	}
+}