From 0df8b231c3d20ee5d0663883503270a9495c337f Mon Sep 17 00:00:00 2001
From: Aleksandr Nogikh <nogikh@google.com>
Date: Wed, 8 Feb 2023 12:48:49 +0100
Subject: pkg/report: add a ReportToGuiltyFile method

We cannot unfortunately just substitute Report and invoke Symbolize(),
because in this case a non-emtpy reportPrefixLen may lead to `panic:
runtime error: slice bounds out`.

Create a special external method in the pkg/report package.
---
 pkg/report/linux.go                  |  7 +++++--
 pkg/report/report.go                 | 14 ++++++++++++++
 tools/syz-fillreports/fillreports.go | 23 +++--------------------
 3 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/pkg/report/linux.go b/pkg/report/linux.go
index b0650339e..0e2d8e1a4 100644
--- a/pkg/report/linux.go
+++ b/pkg/report/linux.go
@@ -691,8 +691,11 @@ func (ctx *linux) decompileOpcodes(text []byte, report *Report) []byte {
 }
 
 func (ctx *linux) extractGuiltyFile(rep *Report) string {
-	report := rep.Report[rep.reportPrefixLen:]
-	if strings.HasPrefix(rep.Title, "INFO: rcu detected stall") {
+	return ctx.extractGuiltyFileRaw(rep.Title, rep.Report[rep.reportPrefixLen:])
+}
+
+func (ctx *linux) extractGuiltyFileRaw(title string, report []byte) string {
+	if strings.HasPrefix(title, "INFO: rcu detected stall") {
 		// Special case for rcu stalls.
 		// There are too many frames that we want to skip before actual guilty frames,
 		// we would need to ignore too many files and that would be fragile.
diff --git a/pkg/report/report.go b/pkg/report/report.go
index 7dd9714b3..77244fcd9 100644
--- a/pkg/report/report.go
+++ b/pkg/report/report.go
@@ -259,6 +259,20 @@ func (reporter *Reporter) isInteresting(rep *Report) bool {
 	return false
 }
 
+// There are cases when we need to extract a guilty file, but have no ability to do it the
+// proper way -- parse and symbolize the raw console output log. One of such cases is
+// the syz-fillreports tool, which only has access to the already symbolized logs.
+// ReportToGuiltyFile does its best to extract the data.
+func (reporter *Reporter) ReportToGuiltyFile(title string, report []byte) string {
+	ii, ok := reporter.impl.(interface {
+		extractGuiltyFileRaw(title string, report []byte) string
+	})
+	if !ok {
+		return ""
+	}
+	return ii.extractGuiltyFileRaw(title, report)
+}
+
 func extractReportType(rep *Report) Type {
 	// Type/frame extraction logic should be integrated with oops types.
 	// But for now we do this more ad-hoc analysis here to at least isolate
diff --git a/tools/syz-fillreports/fillreports.go b/tools/syz-fillreports/fillreports.go
index 501a9bcfa..1a730e95c 100644
--- a/tools/syz-fillreports/fillreports.go
+++ b/tools/syz-fillreports/fillreports.go
@@ -62,32 +62,15 @@ func processReport(dash *dashapi.Dashboard, bugReport *dashapi.BugReport, bugID
 		log.Fatalf("%v: failed to create a reporter for %s/%s",
 			bugReport.ID, bugReport.OS, bugReport.Arch)
 	}
-	rep := reporter.Parse(bugReport.Log)
-	if rep == nil {
-		log.Printf("%v: no crash is detected", bugReport.ID)
-		return
-	}
-	// In order to extract a guilty path, the report needs to be normally symbolized,
-	// and for symbolization we need the kernel object file (e.g. vmlinux) for the
-	// kernel, on which the crash was triggered.
-	// We do not have it for all our crashes, but we can do a hack here -- we already
-	// have a symbolized report on the dashboard, so we can substitute it into the
-	// partially processed Report object. This is not the most robust solution, as
-	// it relies on the internals of how the `Symbolize` method works, but it's short
-	// and works now, and furthermore we do not really have other options.
-	rep.Report = bugReport.Report
-	err = reporter.Symbolize(rep)
-	if err != nil {
-		log.Printf("%v: symbolize failed: %v", bugReport.ID, err)
-	}
-	if rep.GuiltyFile == "" {
+	guiltyFile := reporter.ReportToGuiltyFile(bugReport.Title, bugReport.Report)
+	if guiltyFile == "" {
 		log.Printf("%v: no guilty files extracted", bugReport.ID)
 		return
 	}
 	err = dash.UpdateReport(&dashapi.UpdateReportReq{
 		BugID:       bugID,
 		CrashID:     bugReport.CrashID,
-		GuiltyFiles: &[]string{rep.GuiltyFile},
+		GuiltyFiles: &[]string{guiltyFile},
 	})
 	if err != nil {
 		log.Printf("%v: failed to save: %v", bugReport.ID, err)
-- 
cgit mrf-deployment