3 files changed, 29 insertions, 2 deletions
diff --git a/pkg/mgrconfig/config.go b/pkg/mgrconfig/config.go
index 9073c482c..46270ab0c 100644
--- a/pkg/mgrconfig/config.go
+++ b/pkg/mgrconfig/config.go
@@ -166,6 +166,8 @@ type Config struct {
 	EnabledSyscalls []string `json:"enable_syscalls,omitempty"`
 	// List of system calls that should be treated as disabled (optional).
 	DisabledSyscalls []string `json:"disable_syscalls,omitempty"`
+	// List of syscalls that should not be mutated by the fuzzer (optional).
+	NoMutateSyscalls []string `json:"no_mutate_syscalls,omitempty"`
 	// List of regexps for known bugs.
 	// Don't save reports matching these regexps, but reboot VM after them,
 	// matched against whole report output.
diff --git a/pkg/mgrconfig/load.go b/pkg/mgrconfig/load.go
index 2b49d0cbd..f1063ed17 100644
--- a/pkg/mgrconfig/load.go
+++ b/pkg/mgrconfig/load.go
@@ -34,8 +34,9 @@ type Derived struct {
 	ExecprogBin string
 	ExecutorBin string
 
-	Syscalls []int
-	Timeouts targets.Timeouts
+	Syscalls      []int
+	NoMutateCalls map[int]bool // Set of IDs of syscalls which should not be mutated.
+	Timeouts      targets.Timeouts
 }
 
 func LoadData(data []byte) (*Config, error) {
@@ -177,6 +178,10 @@ func Complete(cfg *Config) error {
 	if err != nil {
 		return err
 	}
+	cfg.NoMutateCalls, err = ParseNoMutateSyscalls(cfg.Target, cfg.NoMutateSyscalls)
+	if err != nil {
+		return err
+	}
 	cfg.initTimeouts()
 	return nil
 }
@@ -329,6 +334,25 @@ func ParseEnabledSyscalls(target *prog.Target, enabled, disabled []string) ([]in
 	return arr, nil
 }
 
+func ParseNoMutateSyscalls(target *prog.Target, syscalls []string) (map[int]bool, error) {
+	var result = make(map[int]bool)
+
+	for _, c := range syscalls {
+		n := 0
+		for _, call := range target.Syscalls {
+			if MatchSyscall(call.Name, c) {
+				result[call.ID] = true
+				n++
+			}
+		}
+		if n == 0 {
+			return nil, fmt.Errorf("unknown no_mutate syscall: %v", c)
+		}
+	}
+
+	return result, nil
+}
+
 func MatchSyscall(name, pattern string) bool {
 	if pattern == name || strings.HasPrefix(name, pattern+"$") {
 		return true
diff --git a/pkg/rpctype/rpctype.go b/pkg/rpctype/rpctype.go
index f1d889a20..fc582e576 100644
--- a/pkg/rpctype/rpctype.go
+++ b/pkg/rpctype/rpctype.go
@@ -41,6 +41,7 @@ type ConnectArgs struct {
 
 type ConnectRes struct {
 	EnabledCalls      []int
+	NoMutateCalls     map[int]bool
 	GitRevision       string
 	TargetRevision    string
 	AllSandboxes      bool