prog: dump orig prog if Deserialize panics

We are seeing some one-off panics during Deserialization
and it's unclear if it's machine memory corrpution or
an actual bug in prog. I leam towards machine memory corruption
but it's impossible to prove without seeing the orig program.

Move git revision to prog and it's more base package
(sys can import prog, prog can't import sys).

Makefile

@@ -58,7 +58,7 @@ GITREVDATE=$(shell git log -n 1 --format="%ad")
 # Reduces build time and binary sizes considerably.
 # That's only needed if you use gdb or nm.
 # If you need that, build manually without these flags.
-GOFLAGS := "-ldflags=-s -w -X github.com/google/syzkaller/sys.GitRevision=$(REV) -X 'github.com/google/syzkaller/sys.gitRevisionDate=$(GITREVDATE)'"
+GOFLAGS := "-ldflags=-s -w -X github.com/google/syzkaller/prog.GitRevision=$(REV) -X 'github.com/google/syzkaller/prog.gitRevisionDate=$(GITREVDATE)'"
 
 GOHOSTFLAGS := $(GOFLAGS)
 GOTARGETFLAGS := $(GOFLAGS)

prog/encoding.go

@@ -204,6 +204,12 @@ const (
 )
 
 func (target *Target) Deserialize(data []byte, mode DeserializeMode) (*Prog, error) {
+	defer func() {
+		if err := recover(); err != nil {
+			panic(fmt.Errorf("%v\ntarget: %v/%v, rev: %v, mode=%v, prog:\n%q",
+				err, target.OS, target.Arch, GitRevision, mode, data))
+		}
+	}()
 	p := newParser(target, data, mode == Strict)
 	prog, err := p.parseProg()
 	if err := p.Err(); err != nil {

prog/meta.go

@@ -0,0 +1,26 @@
+// Copyright 2020 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 prog
+
+import (
+	"strings"
+	"time"
+)
+
+var (
+	GitRevision     string    // emitted by Makefile, may contain + at the end
+	GitRevisionBase string    // without +
+	gitRevisionDate string    // emitted by Makefile
+	GitRevisionDate time.Time // parsed from gitRevisionDate
+)
+
+func init() {
+	GitRevisionBase = strings.Replace(GitRevision, "+", "", -1)
+	if gitRevisionDate != "" {
+		var err error
+		if GitRevisionDate, err = time.Parse("Mon Jan 2 15:04:05 2006 -0700", gitRevisionDate); err != nil {
+			panic(err)
+		}
+	}
+}

sys/sys.go

@@ -4,9 +4,6 @@
 package sys
 
 import (
-	"strings"
-	"time"
-
 	// Import all targets, so that users only need to import sys.
 	_ "github.com/google/syzkaller/sys/akaros/gen"
 	_ "github.com/google/syzkaller/sys/freebsd/gen"
@@ -17,20 +14,3 @@ import (
 	_ "github.com/google/syzkaller/sys/test/gen"
 	_ "github.com/google/syzkaller/sys/windows/gen"
 )
-
-var (
-	GitRevision     string    // emitted by Makefile, may contain + at the end
-	GitRevisionBase string    // without +
-	gitRevisionDate string    // emitted by Makefile
-	GitRevisionDate time.Time // parsed from gitRevisionDate
-)
-
-func init() {
-	GitRevisionBase = strings.Replace(GitRevision, "+", "", -1)
-	if gitRevisionDate != "" {
-		var err error
-		if GitRevisionDate, err = time.Parse("Mon Jan 2 15:04:05 2006 -0700", gitRevisionDate); err != nil {
-			panic(err)
-		}
-	}
-}

syz-ci/manager.go

@@ -23,7 +23,8 @@ import (
 	"github.com/google/syzkaller/pkg/osutil"
 	"github.com/google/syzkaller/pkg/report"
 	"github.com/google/syzkaller/pkg/vcs"
-	"github.com/google/syzkaller/sys"
+	"github.com/google/syzkaller/prog"
+	_ "github.com/google/syzkaller/sys"
 	"github.com/google/syzkaller/sys/targets"
 	"github.com/google/syzkaller/vm"
 )
@@ -530,7 +531,7 @@ func (mgr *Manager) createDashboardBuild(info *BuildInfo, imageDir, typ string)
 	// Also mix in build type, so that image error builds are not merged into normal builds.
 	var tagData []byte
 	tagData = append(tagData, info.Tag...)
-	tagData = append(tagData, sys.GitRevisionBase...)
+	tagData = append(tagData, prog.GitRevisionBase...)
 	tagData = append(tagData, typ...)
 	build := &dashapi.Build{
 		Manager:             mgr.name,
@@ -538,8 +539,8 @@ func (mgr *Manager) createDashboardBuild(info *BuildInfo, imageDir, typ string)
 		OS:                  mgr.managercfg.TargetOS,
 		Arch:                mgr.managercfg.TargetArch,
 		VMArch:              mgr.managercfg.TargetVMArch,
-		SyzkallerCommit:     sys.GitRevisionBase,
-		SyzkallerCommitDate: sys.GitRevisionDate,
+		SyzkallerCommit:     prog.GitRevisionBase,
+		SyzkallerCommitDate: prog.GitRevisionDate,
 		CompilerID:          info.CompilerID,
 		KernelRepo:          info.KernelRepo,
 		KernelBranch:        info.KernelBranch,

syz-ci/updater.go

@@ -17,7 +17,7 @@ import (
 	"github.com/google/syzkaller/pkg/log"
 	"github.com/google/syzkaller/pkg/osutil"
 	"github.com/google/syzkaller/pkg/vcs"
-	"github.com/google/syzkaller/sys"
+	"github.com/google/syzkaller/prog"
 )
 
 const (
@@ -119,7 +119,7 @@ func (upd *SyzUpdater) UpdateOnStart(autoupdate bool, shutdown chan struct{}) {
 		if st, err := os.Stat(upd.exe); err == nil {
 			exeMod = st.ModTime()
 		}
-		uptodate := sys.GitRevisionBase == latestTag && time.Since(exeMod) < time.Minute
+		uptodate := prog.GitRevisionBase == latestTag && time.Since(exeMod) < time.Minute
 		if uptodate || !autoupdate {
 			if uptodate {
 				// Have a fresh up-to-date build, probably just restarted.
@@ -133,11 +133,11 @@ func (upd *SyzUpdater) UpdateOnStart(autoupdate bool, shutdown chan struct{}) {
 			return
 		}
 	}
-	log.Logf(0, "current executable is on %v", sys.GitRevision)
+	log.Logf(0, "current executable is on %v", prog.GitRevision)
 	log.Logf(0, "latest syzkaller build is on %v", latestTag)
 
 	// No syzkaller build or executable is stale.
-	lastCommit := sys.GitRevisionBase
+	lastCommit := prog.GitRevisionBase
 	for {
 		lastCommit = upd.pollAndBuild(lastCommit)
 		latestTag := upd.checkLatest()
@@ -148,7 +148,7 @@ func (upd *SyzUpdater) UpdateOnStart(autoupdate bool, shutdown chan struct{}) {
 			if err := osutil.LinkFiles(upd.latestDir, upd.currentDir, upd.syzFiles); err != nil {
 				log.Fatal(err)
 			}
-			if autoupdate && sys.GitRevisionBase != latestTag {
+			if autoupdate && prog.GitRevisionBase != latestTag {
 				upd.UpdateAndRestart()
 			}
 			return

syz-fuzzer/testing.go

@@ -17,7 +17,6 @@ import (
 	"github.com/google/syzkaller/pkg/rpctype"
 	"github.com/google/syzkaller/pkg/runtest"
 	"github.com/google/syzkaller/prog"
-	"github.com/google/syzkaller/sys"
 )
 
 type checkArgs struct {
@@ -203,13 +202,13 @@ func checkRevisions(args *checkArgs) error {
 	if args.target.Arch != vers[1] {
 		return fmt.Errorf("mismatching target/executor arches: %v vs %v", args.target.Arch, vers[1])
 	}
-	if sys.GitRevision != vers[3] {
+	if prog.GitRevision != vers[3] {
 		return fmt.Errorf("mismatching fuzzer/executor git revisions: %v vs %v",
-			sys.GitRevision, vers[3])
+			prog.GitRevision, vers[3])
 	}
-	if args.gitRevision != "" && args.gitRevision != sys.GitRevision {
+	if args.gitRevision != "" && args.gitRevision != prog.GitRevision {
 		return fmt.Errorf("mismatching manager/fuzzer git revisions: %v vs %v",
-			args.gitRevision, sys.GitRevision)
+			args.gitRevision, prog.GitRevision)
 	}
 	if args.target.Revision != vers[2] {
 		return fmt.Errorf("mismatching fuzzer/executor system call descriptions: %v vs %v",

syz-manager/html.go

@@ -27,7 +27,6 @@ import (
 	"github.com/google/syzkaller/pkg/signal"
 	"github.com/google/syzkaller/pkg/vcs"
 	"github.com/google/syzkaller/prog"
-	"github.com/google/syzkaller/sys"
 )
 
 func (mgr *Manager) initHTTP() {
@@ -112,7 +111,7 @@ func (mgr *Manager) collectStats() []UIStat {
 	defer mgr.mu.Unlock()
 
 	rawStats := mgr.stats.all()
-	head := sys.GitRevisionBase
+	head := prog.GitRevisionBase
 	stats := []UIStat{
 		{Name: "revision", Value: fmt.Sprint(head[:8]), Link: vcs.LogLink(vcs.SyzkallerRepo, head)},
 		{Name: "config", Value: mgr.cfg.Name, Link: "/config"},

syz-manager/manager.go

@@ -33,7 +33,6 @@ import (
 	"github.com/google/syzkaller/pkg/rpctype"
 	"github.com/google/syzkaller/pkg/signal"
 	"github.com/google/syzkaller/prog"
-	"github.com/google/syzkaller/sys"
 	"github.com/google/syzkaller/sys/targets"
 	"github.com/google/syzkaller/vm"
 )
@@ -112,7 +111,7 @@ type Crash struct {
 }
 
 func main() {
-	if sys.GitRevision == "" {
+	if prog.GitRevision == "" {
 		log.Fatalf("Bad syz-manager build. Build with make, run bin/syz-manager.")
 	}
 	flag.Parse()

syz-manager/rpc.go

@@ -15,7 +15,6 @@ import (
 	"github.com/google/syzkaller/pkg/rpctype"
 	"github.com/google/syzkaller/pkg/signal"
 	"github.com/google/syzkaller/prog"
-	"github.com/google/syzkaller/sys"
 )
 
 type RPCServer struct {
@@ -97,7 +96,7 @@ func (serv *RPCServer) Connect(a *rpctype.ConnectArgs, r *rpctype.ConnectRes) er
 	r.MemoryLeakFrames = bugFrames.memoryLeaks
 	r.DataRaceFrames = bugFrames.dataRaces
 	r.EnabledCalls = serv.enabledSyscalls
-	r.GitRevision = sys.GitRevision
+	r.GitRevision = prog.GitRevision
 	r.TargetRevision = serv.target.Revision
 	// TODO: temporary disabled b/c we suspect this negatively affects fuzzing.
 	if false && serv.mgr.rotateCorpus() && serv.rnd.Intn(3) != 0 {

tools/syz-runtest/runtest.go

@@ -26,7 +26,7 @@ import (
 	"github.com/google/syzkaller/pkg/rpctype"
 	"github.com/google/syzkaller/pkg/runtest"
 	"github.com/google/syzkaller/prog"
-	"github.com/google/syzkaller/sys"
+	_ "github.com/google/syzkaller/sys"
 	"github.com/google/syzkaller/sys/targets"
 	"github.com/google/syzkaller/vm"
 )
@@ -213,7 +213,7 @@ func (mgr *Manager) finishRequest(name string, rep *report.Report) error {
 }
 
 func (mgr *Manager) Connect(a *rpctype.ConnectArgs, r *rpctype.ConnectRes) error {
-	r.GitRevision = sys.GitRevision
+	r.GitRevision = prog.GitRevision
 	r.TargetRevision = mgr.target.Revision
 	r.AllSandboxes = true
 	select {