all: record diverted bug reproductions

In some cases, we derail during bug reproduction and end up finding and
reporting a reproducer for another issue. It causes no problems since
it's bucketed using the new title, but it's difficult to trace such
situations - on the original bug page, there are no failed reproduction
logs and on the new bug page it looks as if we intended to find a
reproducer for the bug with the new title.

Let's record bug reproduction logs in this case, so that we'd also see
a failed bug reproduction attempt on the original bug page.

4 files changed, 93 insertions, 34 deletions

diff --git a/dashboard/app/api.go b/dashboard/app/api.go
index 63a41c6d8..ba6212da1 100644
--- a/dashboard/app/api.go
+++ b/dashboard/app/api.go
@@ -721,10 +721,25 @@ func apiReportCrash(c context.Context, ns string, r *http.Request, payload []byt
 	if !getNsConfig(c, ns).TransformCrash(build, req) {
 		return new(dashapi.ReportCrashResp), nil
 	}
+	var bug2 *Bug
+	if req.OriginalTitle != "" {
+		bug2, err = findExistingBugForCrash(c, ns, []string{req.OriginalTitle})
+		if err != nil {
+			return nil, fmt.Errorf("original bug query failed: %w", err)
+		}
+	}
 	bug, err := reportCrash(c, build, req)
 	if err != nil {
 		return nil, err
 	}
+	if bug2 != nil && bug2.Title != bug.Title && len(req.ReproLog) > 0 {
+		// During bug reproduction, we have diverted to another bug.
+		// Let's remember this.
+		err = saveFailedReproLog(c, bug2, build, req.ReproLog)
+		if err != nil {
+			return nil, fmt.Errorf("failed to save failed repro log: %w", err)
+		}
+	}
 	resp := &dashapi.ReportCrashResp{
 		NeedRepro: needRepro(c, bug),
 	}
@@ -1011,12 +1026,16 @@ func apiReportFailedRepro(c context.Context, ns string, r *http.Request, payload
 	if bug == nil {
 		return nil, fmt.Errorf("%v: can't find bug for crash %q", ns, req.Title)
 	}
-	bugKey := bug.key(c)
 	build, err := loadBuild(c, ns, req.BuildID)
 	if err != nil {
 		return nil, err
 	}
+	return nil, saveFailedReproLog(c, bug, build, req.ReproLog)
+}
+
+func saveFailedReproLog(c context.Context, bug *Bug, build *Build, log []byte) error {
 	now := timeNow(c)
+	bugKey := bug.key(c)
 	tx := func(c context.Context) error {
 		bug := new(Bug)
 		if err := db.Get(c, bugKey, bug); err != nil {
@@ -1024,8 +1043,8 @@ func apiReportFailedRepro(c context.Context, ns string, r *http.Request, payload
 		}
 		bug.NumRepro++
 		bug.LastReproTime = now
-		if len(req.ReproLog) > 0 {
-			err := saveReproLog(c, bug, build, req.ReproLog)
+		if len(log) > 0 {
+			err := saveReproAttempt(c, bug, build, log)
 			if err != nil {
 				return fmt.Errorf("failed to save repro log: %w", err)
 			}
@@ -1035,16 +1054,15 @@ func apiReportFailedRepro(c context.Context, ns string, r *http.Request, payload
 		}
 		return nil
 	}
-	err = db.RunInTransaction(c, tx, &db.TransactionOptions{
+	return db.RunInTransaction(c, tx, &db.TransactionOptions{
 		XG:       true,
 		Attempts: 30,
 	})
-	return nil, err
 }
 
 const maxReproLogs = 5
 
-func saveReproLog(c context.Context, bug *Bug, build *Build, log []byte) error {
+func saveReproAttempt(c context.Context, bug *Bug, build *Build, log []byte) error {
 	var deleteKeys []*db.Key
 	for len(bug.ReproAttempts)+1 > maxReproLogs {
 		deleteKeys = append(deleteKeys,
diff --git a/dashboard/app/repro_test.go b/dashboard/app/repro_test.go
index c6b6bec4f..8c587324e 100644
--- a/dashboard/app/repro_test.go
+++ b/dashboard/app/repro_test.go
@@ -450,3 +450,38 @@ func TestLogToReproduce(t *testing.T) {
 	c.expectOK(err)
 	c.expectEQ(resp.CrashLog, []byte(nil))
 }
+
+// A frequent case -- when trying to find a reproducer for one bug,
+// we have found a reproducer for a different bug.
+// We want to remember the reproduction log in this case.
+func TestReproForDifferentCrash(t *testing.T) {
+	c := NewCtx(t)
+	defer c.Close()
+
+	client := c.client
+	build := testBuild(1)
+	client.UploadBuild(build)
+
+	// Original crash.
+	crash := &dashapi.Crash{
+		BuildID: "build1",
+		Title:   "title1",
+		Log:     []byte("log1"),
+		Report:  []byte("report1"),
+	}
+	client.ReportCrash(crash)
+	oldBug := client.pollBug()
+
+	// Now we have "found" a reproducer with a different title.
+	crash.Title = "new title"
+	crash.ReproOpts = []byte("opts")
+	crash.ReproSyz = []byte("repro syz")
+	crash.ReproLog = []byte("repro log")
+	crash.OriginalTitle = "title1"
+	client.ReportCrash(crash)
+	client.pollBug()
+
+	// Ensure that we have saved the reproduction log in this case.
+	dbBug, _, _ := c.loadBug(oldBug.ID)
+	c.expectEQ(len(dbBug.ReproAttempts), 1)
+}
diff --git a/dashboard/dashapi/dashapi.go b/dashboard/dashapi/dashapi.go
index ed9152e09..37aebc631 100644
--- a/dashboard/dashapi/dashapi.go
+++ b/dashboard/dashapi/dashapi.go
@@ -323,9 +323,11 @@ type Crash struct {
 	Assets      []NewAsset
 	GuiltyFiles []string
 	// The following is optional and is filled only after repro.
-	ReproOpts []byte
-	ReproSyz  []byte
-	ReproC    []byte
+	ReproOpts     []byte
+	ReproSyz      []byte
+	ReproC        []byte
+	ReproLog      []byte
+	OriginalTitle string // Title before we began bug reproduction.
 }
 
 type ReportCrashResp struct {
diff --git a/syz-manager/manager.go b/syz-manager/manager.go
index 3ae8caf1a..1ef1f18ea 100644
--- a/syz-manager/manager.go
+++ b/syz-manager/manager.go
@@ -317,13 +317,14 @@ type RunResult struct {
 }
 
 type ReproResult struct {
-	instances []int
-	report0   *report.Report // the original report we started reproducing
-	repro     *repro.Result
-	strace    *repro.StraceResult
-	stats     *repro.Stats
-	err       error
-	external  bool // repro came from hub or dashboard
+	instances     []int
+	report0       *report.Report // the original report we started reproducing
+	repro         *repro.Result
+	strace        *repro.StraceResult
+	stats         *repro.Stats
+	err           error
+	external      bool   // repro came from hub or dashboard
+	originalTitle string // crash title before we started bug reproduction
 }
 
 // Manager needs to be refactored (#605).
@@ -498,12 +499,13 @@ func (mgr *Manager) runRepro(crash *Crash, vmIndexes []int, putInstances func(..
 	features := mgr.checkResult.Features
 	res, stats, err := repro.Run(crash.Output, mgr.cfg, features, mgr.reporter, mgr.vmPool, vmIndexes)
 	ret := &ReproResult{
-		instances: vmIndexes,
-		report0:   crash.Report,
-		repro:     res,
-		stats:     stats,
-		err:       err,
-		external:  crash.external,
+		instances:     vmIndexes,
+		report0:       crash.Report,
+		repro:         res,
+		stats:         stats,
+		err:           err,
+		external:      crash.external,
+		originalTitle: crash.Title,
 	}
 	if err == nil && res != nil && mgr.cfg.StraceBin != "" {
 		// We need only one instance to get strace output, release the rest.
@@ -1101,18 +1103,20 @@ func (mgr *Manager) saveRepro(res *ReproResult) {
 		}
 
 		dc := &dashapi.Crash{
-			BuildID:    mgr.cfg.Tag,
-			Title:      report.Title,
-			AltTitles:  report.AltTitles,
-			Suppressed: report.Suppressed,
-			Recipients: report.Recipients.ToDash(),
-			Log:        output,
-			Flags:      crashFlags,
-			Report:     report.Report,
-			ReproOpts:  repro.Opts.Serialize(),
-			ReproSyz:   progText,
-			ReproC:     cprogText,
-			Assets:     mgr.uploadReproAssets(repro),
+			BuildID:       mgr.cfg.Tag,
+			Title:         report.Title,
+			AltTitles:     report.AltTitles,
+			Suppressed:    report.Suppressed,
+			Recipients:    report.Recipients.ToDash(),
+			Log:           output,
+			Flags:         crashFlags,
+			Report:        report.Report,
+			ReproOpts:     repro.Opts.Serialize(),
+			ReproSyz:      progText,
+			ReproC:        cprogText,
+			ReproLog:      fullReproLog(res.stats),
+			Assets:        mgr.uploadReproAssets(repro),
+			OriginalTitle: res.originalTitle,
 		}
 		setGuiltyFiles(dc, report)
 		if _, err := mgr.dash.ReportCrash(dc); err != nil {