From fc3c67f0292ef665a4d6b68d2cb3a25a793a061f Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Wed, 28 Oct 2020 17:37:53 +0100
Subject: syz-manager: don't fail on the first machine check error

Machine check may be a bit flaky in some contexts
(e.g. due to a random timeout flake). Don't fail everything
on the first machine check error. Give it 10 tries.
---
 syz-manager/manager.go |  3 ---
 syz-manager/rpc.go     | 25 +++++++++++++++++--------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/syz-manager/manager.go b/syz-manager/manager.go
index bac2a773a..3942e12d5 100644
--- a/syz-manager/manager.go
+++ b/syz-manager/manager.go
@@ -1080,9 +1080,6 @@ func (mgr *Manager) machineChecked(a *rpctype.CheckArgs, enabledSyscalls map[*pr
 			}
 		}
 	}
-	if a.Error != "" {
-		log.Fatalf("machine check: %v", a.Error)
-	}
 	log.Logf(0, "machine check:")
 	log.Logf(0, "%-24v: %v/%v", "syscalls", len(enabledSyscalls), len(mgr.target.Syscalls))
 	for _, feat := range a.Features.Supported() {
diff --git a/syz-manager/rpc.go b/syz-manager/rpc.go
index 3cd3d2d08..add55f031 100644
--- a/syz-manager/rpc.go
+++ b/syz-manager/rpc.go
@@ -27,14 +27,15 @@ type RPCServer struct {
 	sandbox               string
 	batchSize             int
 
-	mu           sync.Mutex
-	fuzzers      map[string]*Fuzzer
-	checkResult  *rpctype.CheckArgs
-	maxSignal    signal.Signal
-	corpusSignal signal.Signal
-	corpusCover  cover.Cover
-	rotator      *prog.Rotator
-	rnd          *rand.Rand
+	mu            sync.Mutex
+	fuzzers       map[string]*Fuzzer
+	checkResult   *rpctype.CheckArgs
+	maxSignal     signal.Signal
+	corpusSignal  signal.Signal
+	corpusCover   cover.Cover
+	rotator       *prog.Rotator
+	rnd           *rand.Rand
+	checkFailures int
 }
 
 type Fuzzer struct {
@@ -198,6 +199,14 @@ func (serv *RPCServer) Check(a *rpctype.CheckArgs, r *int) error {
 	if serv.checkResult != nil {
 		return nil
 	}
+	if a.Error != "" {
+		log.Logf(0, "machine check failed: %v", a.Error)
+		serv.checkFailures++
+		if serv.checkFailures == 10 {
+			log.Fatalf("machine check failing")
+		}
+		return fmt.Errorf("you failed")
+	}
 	serv.targetEnabledSyscalls = make(map[*prog.Syscall]bool)
 	for _, call := range a.EnabledCalls[serv.sandbox] {
 		serv.targetEnabledSyscalls[serv.target.Syscalls[call]] = true
-- 
cgit mrf-deployment