pkg/mgrconfig: allow to disable remote coverage and coverage edges

4 files changed, 25 insertions, 9 deletions

diff --git a/executor/executor.cc b/executor/executor.cc
index fb5d242de..862b0776e 100644
--- a/executor/executor.cc
+++ b/executor/executor.cc
@@ -990,13 +990,15 @@ void execute_one()
 #endif
 
 	write_extra_output();
-	// Check for new extra coverage in small intervals to avoid situation
-	// that we were killed on timeout before we write any.
-	// Check for extra coverage is very cheap, effectively a memory load.
-	const uint64 kSleepMs = 100;
-	for (uint64 i = 0; i < prog_extra_cover_timeout / kSleepMs; i++) {
-		sleep_ms(kSleepMs);
-		write_extra_output();
+	if (flag_extra_coverage) {
+		// Check for new extra coverage in small intervals to avoid situation
+		// that we were killed on timeout before we write any.
+		// Check for extra coverage is very cheap, effectively a memory load.
+		const uint64 kSleepMs = 100;
+		for (uint64 i = 0; i < prog_extra_cover_timeout / kSleepMs; i++) {
+			sleep_ms(kSleepMs);
+			write_extra_output();
+		}
 	}
 }
 
diff --git a/pkg/mgrconfig/config.go b/pkg/mgrconfig/config.go
index 461d25afb..5b383249a 100644
--- a/pkg/mgrconfig/config.go
+++ b/pkg/mgrconfig/config.go
@@ -217,6 +217,12 @@ type Experimental struct {
 	// Don't let the VM state accumulate too much by restarting
 	// syz-executor before most prog executions.
 	ResetAccState bool `json:"reset_acc_state"`
+
+	// Use KCOV remote coverage feature (default: true).
+	RemoteCover bool `json:"remote_cover"`
+
+	// Hash adjacent PCs to form fuzzing feedback signal, otherwise use PCs as signal (default: true).
+	CoverEdges bool `json:"cover_edges"`
 }
 
 type Subsystem struct {
diff --git a/pkg/mgrconfig/load.go b/pkg/mgrconfig/load.go
index ba446ffa3..05ba38a98 100644
--- a/pkg/mgrconfig/load.go
+++ b/pkg/mgrconfig/load.go
@@ -90,6 +90,10 @@ func defaultValues() *Config {
 		MaxCrashLogs:   100,
 		Procs:          6,
 		PreserveCorpus: true,
+		Experimental: Experimental{
+			RemoteCover: true,
+			CoverEdges:  true,
+		},
 	}
 }
 
diff --git a/pkg/rpcserver/rpcserver.go b/pkg/rpcserver/rpcserver.go
index cdeb6f40b..58ef2d363 100644
--- a/pkg/rpcserver/rpcserver.go
+++ b/pkg/rpcserver/rpcserver.go
@@ -85,10 +85,14 @@ func New(cfg *mgrconfig.Config, mgr Manager, debug bool) (*Server, error) {
 	if err != nil {
 		return nil, err
 	}
+	features := flatrpc.AllFeatures
+	if !cfg.Experimental.RemoteCover {
+		features &= ^flatrpc.FeatureExtraCoverage
+	}
 	return newImpl(&Config{
 		Config: vminfo.Config{
 			Target:     cfg.Target,
-			Features:   flatrpc.AllFeatures,
+			Features:   features,
 			Syscalls:   cfg.Syscalls,
 			Debug:      debug,
 			Cover:      cfg.Cover,
@@ -99,7 +103,7 @@ func New(cfg *mgrconfig.Config, mgr Manager, debug bool) (*Server, error) {
 		RPC:    cfg.RPC,
 		VMLess: cfg.VMLess,
 		// gVisor coverage is not a trace, so producing edges won't work.
-		UseCoverEdges: cfg.Type != targets.GVisor,
+		UseCoverEdges: cfg.Experimental.CoverEdges && cfg.Type != targets.GVisor,
 		// gVisor/Starnix are not Linux, so filtering against Linux ranges won't work.
 		FilterSignal:      cfg.Type != targets.GVisor && cfg.Type != targets.Starnix,
 		PrintMachineCheck: true,