Explicitly pass readOnly flag

core/vm/evm.go

@@ -400,7 +400,10 @@ func (evm *EVM) StaticCall(caller ContractRef, addr common.Address, input []byte
 	}
 
 	if p, isPrecompile := evm.precompile(addr); isPrecompile {
-		ret, gas, err = RunStatefulPrecompiledContract(p, evm, caller.Address(), addr, input, gas, evm.interpreter.readOnly)
+		// Explicitly pass readOnly as true for StaticCall OpCode.
+		// Precompile implementation is responsible for honoring readOnly flag.
+		// No state should be modified, return an error instead.
+		ret, gas, err = RunStatefulPrecompiledContract(p, evm, caller.Address(), addr, input, gas, true)
 	} else {
 		// At this point, we use a copy of address. If we don't, the go compiler will
 		// leak the 'contract' to the outer scope, and make allocation for 'contract'