pkg/manager: store titles stat in the crash dir

3 files changed, 167 insertions, 0 deletions

diff --git a/pkg/manager/crash.go b/pkg/manager/crash.go
index cc36db721..f0fa58959 100644
--- a/pkg/manager/crash.go
+++ b/pkg/manager/crash.go
@@ -91,6 +91,9 @@ func (cs *CrashStore) SaveCrash(crash *Crash) (bool, error) {
 	writeOrRemove("tag", []byte(cs.Tag))
 	writeOrRemove("report", report.MergeReportBytes(reps))
 	writeOrRemove("machineInfo", crash.MachineInfo)
+	if err := report.AddTitleStat(filepath.Join(dir, "title-stat"), reps); err != nil {
+		return false, fmt.Errorf("report.AddTitleStat: %w", err)
+	}
 
 	return first, nil
 }
diff --git a/pkg/report/title_stat.go b/pkg/report/title_stat.go
new file mode 100644
index 000000000..92d8079d5
--- /dev/null
+++ b/pkg/report/title_stat.go
@@ -0,0 +1,88 @@
+// Copyright 2025 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package report
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"maps"
+	"os"
+)
+
+func AddTitleStat(file string, reps []*Report) error {
+	var titles []string
+	for _, rep := range reps {
+		titles = append(titles, rep.Title)
+	}
+	stat, err := readStatFile(file)
+	if err != nil {
+		return fmt.Errorf("readStatFile: %w", err)
+	}
+	stat.add(titles)
+	if err := writeStatFile(file, stat); err != nil {
+		return fmt.Errorf("writeStatFile: %w", err)
+	}
+	return nil
+}
+
+func readStatFile(file string) (*titleStat, error) {
+	stat := &titleStat{}
+	if _, err := os.Stat(file); errors.Is(err, os.ErrNotExist) {
+		return stat, nil
+	}
+	data, err := os.ReadFile(file)
+	if err != nil {
+		return nil, err
+	}
+	if len(data) == 0 {
+		return stat, nil
+	}
+	if err := json.Unmarshal(data, stat); err != nil {
+		return nil, err
+	}
+	return stat, nil
+}
+
+func writeStatFile(file string, stat *titleStat) error {
+	data, err := json.MarshalIndent(stat, "", "\t")
+	if err != nil {
+		return err
+	}
+	if err := os.WriteFile(file, data, 0644); err != nil {
+		return err
+	}
+	return nil
+}
+
+type titleStatNodes map[string]*titleStat
+
+type titleStat struct {
+	Count int
+	Nodes titleStatNodes
+}
+
+func (ts *titleStat) add(reps []string) {
+	if len(reps) == 0 {
+		return
+	}
+	if ts.Nodes == nil {
+		ts.Nodes = make(titleStatNodes)
+	}
+	if ts.Nodes[reps[0]] == nil {
+		ts.Nodes[reps[0]] = &titleStat{}
+	}
+	ts.Nodes[reps[0]].Count++
+	ts.Nodes[reps[0]].add(reps[1:])
+}
+
+func (ts *titleStat) visit(cb func(int, ...string), titles ...string) {
+	if len(ts.Nodes) == 0 {
+		cb(ts.Count, titles...)
+		return
+	}
+	for title := range maps.Keys(ts.Nodes) {
+		ts.Nodes[title].visit(cb, append(titles, title)...)
+	}
+}
diff --git a/pkg/report/title_stat_test.go b/pkg/report/title_stat_test.go
new file mode 100644
index 000000000..216af456c
--- /dev/null
+++ b/pkg/report/title_stat_test.go
@@ -0,0 +1,76 @@
+// Copyright 2025 syzkaller project authors. All rights reserved.
+// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
+
+package report
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAddTitleStat(t *testing.T) {
+	tests := []struct {
+		name string
+		base string
+		reps [][]*Report
+		want *titleStat
+	}{
+		{
+			name: "read empty",
+			want: &titleStat{},
+		},
+		{
+			name: "add single",
+			reps: [][]*Report{{{Title: "warning 1"}}},
+			want: &titleStat{
+				Nodes: titleStatNodes{
+					"warning 1": {Count: 1},
+				},
+			},
+		},
+		{
+			name: "add chain",
+			reps: [][]*Report{{{Title: "warning 1"}, {Title: "warning 2"}}},
+			want: &titleStat{
+				Nodes: titleStatNodes{
+					"warning 1": {Count: 1,
+						Nodes: titleStatNodes{
+							"warning 2": {Count: 1},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "add multi chains",
+			reps: [][]*Report{{{Title: "warning 1"}, {Title: "warning 2"}}, {{Title: "warning 1"}, {Title: "warning 3"}}},
+			want: &titleStat{
+				Nodes: titleStatNodes{
+					"warning 1": {Count: 2,
+						Nodes: titleStatNodes{
+							"warning 2": {Count: 1},
+							"warning 3": {Count: 1},
+						},
+					},
+				},
+			},
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+			tmpFile := t.TempDir() + "/test.input"
+			err := os.WriteFile(tmpFile, []byte(test.base), 0644)
+			assert.NoError(t, err)
+			for _, reps := range test.reps {
+				err = AddTitleStat(tmpFile, reps)
+				assert.NoError(t, err)
+			}
+			got, err := ReadStatFile(tmpFile)
+			assert.NoError(t, err)
+			assert.Equal(t, test.want, got)
+		})
+	}
+}