diff --git a/src/drivers/airspeed/airspeed.h b/src/drivers/airspeed/airspeed.h
index 0b8e949c9d..d6a88714b6 100644
--- a/src/drivers/airspeed/airspeed.h
+++ b/src/drivers/airspeed/airspeed.h
@@ -107,6 +107,10 @@ private:
 	RingBuffer		*_reports;
 	perf_counter_t		_buffer_overflows;
 
+	/* this class has pointer data members and should not be copied */
+	Airspeed(const Airspeed&);
+	Airspeed& operator=(const Airspeed&);
+
 protected:
 	virtual int	probe();
 
diff --git a/src/drivers/device/i2c.h b/src/drivers/device/i2c.h
index 5498793523..705b398b05 100644
--- a/src/drivers/device/i2c.h
+++ b/src/drivers/device/i2c.h
@@ -138,6 +138,9 @@ private:
 	uint16_t		_address;
 	uint32_t		_frequency;
 	struct i2c_dev_s	*_dev;
+
+	I2C(const device::I2C&);
+	I2C operator=(const device::I2C&);
 };
 
 } // namespace device
diff --git a/src/drivers/device/ringbuffer.h b/src/drivers/device/ringbuffer.h
index a9e22eaa6b..b26e2e7c83 100644
--- a/src/drivers/device/ringbuffer.h
+++ b/src/drivers/device/ringbuffer.h
@@ -162,6 +162,10 @@ private:
 	volatile unsigned	_tail;	/**< removal point in _item_size units */
 
 	unsigned		_next(unsigned index);
+
+	/* we don't want this class to be copied */
+	RingBuffer(const RingBuffer&);
+	RingBuffer operator=(const RingBuffer&);
 };
 
 RingBuffer::RingBuffer(unsigned num_items, size_t item_size) :
diff --git a/src/drivers/device/spi.h b/src/drivers/device/spi.h
index 54849c8c37..1d98376898 100644
--- a/src/drivers/device/spi.h
+++ b/src/drivers/device/spi.h
@@ -129,10 +129,15 @@ private:
 	uint32_t		_frequency;
 	struct spi_dev_s	*_dev;
 
+	/* this class does not allow copying */
+	SPI(const SPI&);
+	SPI operator=(const SPI&);
+
 protected:
 	int			_bus;
 
 	int	_transfer(uint8_t *send, uint8_t *recv, unsigned len);
+
 };
 
 } // namespace device
diff --git a/src/drivers/ets_airspeed/ets_airspeed.cpp b/src/drivers/ets_airspeed/ets_airspeed.cpp
index c15a0cee43..f98d615a2c 100644
--- a/src/drivers/ets_airspeed/ets_airspeed.cpp
+++ b/src/drivers/ets_airspeed/ets_airspeed.cpp
@@ -286,6 +286,9 @@ void	info();
 
 /**
  * Start the driver.
+ *
+ * This function only returns if the sensor is up and running
+ * or could not be detected successfully.
  */
 void
 start(int i2c_bus)
diff --git a/src/drivers/ets_airspeed/module.mk b/src/drivers/ets_airspeed/module.mk
index 15346c5c55..966a5b8190 100644
--- a/src/drivers/ets_airspeed/module.mk
+++ b/src/drivers/ets_airspeed/module.mk
@@ -36,6 +36,7 @@
 #
 
 MODULE_COMMAND		= ets_airspeed
-MODULE_STACKSIZE	= 2048
 
 SRCS			= ets_airspeed.cpp
+
+MODULE_STACKSIZE	= 1200
diff --git a/src/drivers/hmc5883/hmc5883.cpp b/src/drivers/hmc5883/hmc5883.cpp
index f229ecc325..0e9a961ac7 100644
--- a/src/drivers/hmc5883/hmc5883.cpp
+++ b/src/drivers/hmc5883/hmc5883.cpp
@@ -338,6 +338,9 @@ private:
 	 */
 	 int 			check_offset();
 
+	/* this class has pointer data members, do not allow copying it */
+	HMC5883(const HMC5883&);
+	HMC5883 operator=(const HMC5883&);
 };
 
 /*
@@ -348,8 +351,10 @@ extern "C" __EXPORT int hmc5883_main(int argc, char *argv[]);
 
 HMC5883::HMC5883(int bus, const char *path, enum Rotation rotation) :
 	I2C("HMC5883", path, bus, HMC5883L_ADDRESS, 400000),
+	_work{},
 	_measure_ticks(0),
 	_reports(nullptr),
+	_scale{},
 	_range_scale(0), /* default range scale from counts to gauss */
 	_range_ga(1.3f),
 	_collect_phase(false),
@@ -1174,7 +1179,7 @@ int HMC5883::calibrate(struct file *filp, unsigned enable)
 out:
 
 	if (OK != ioctl(filp, MAGIOCSSCALE, (long unsigned int)&mscale_previous)) {
-		warn("WARNING: failed to set new scale / offsets for mag");
+		warn("failed to set new scale / offsets for mag");
 	}
 
 	/* set back to normal mode */
@@ -1370,6 +1375,9 @@ void	usage();
 
 /**
  * Start the driver.
+ *
+ * This function call only returns once the driver
+ * is either successfully up and running or failed to start.
  */
 void
 start(int bus, enum Rotation rotation)
@@ -1465,7 +1473,7 @@ test(int bus)
 	int fd = open(path, O_RDONLY);
 
 	if (fd < 0)
-		err(1, "%s open failed (try 'hmc5883 start' if the driver is not running", path);
+		err(1, "%s open failed (try 'hmc5883 start')", path);
 
 	/* do a simple demand read */
 	sz = read(fd, &report, sizeof(report));
diff --git a/src/drivers/hmc5883/module.mk b/src/drivers/hmc5883/module.mk
index 07377556d3..5daa01dc57 100644
--- a/src/drivers/hmc5883/module.mk
+++ b/src/drivers/hmc5883/module.mk
@@ -37,7 +37,8 @@
 
 MODULE_COMMAND	= hmc5883
 
-# XXX seems excessive, check if 2048 is sufficient
-MODULE_STACKSIZE	= 4096
-
 SRCS		= hmc5883.cpp
+
+MODULE_STACKSIZE	= 1200
+
+EXTRACXXFLAGS	= -Weffc++
diff --git a/src/drivers/l3gd20/l3gd20.cpp b/src/drivers/l3gd20/l3gd20.cpp
index 5e90733ff3..cfae8761c6 100644
--- a/src/drivers/l3gd20/l3gd20.cpp
+++ b/src/drivers/l3gd20/l3gd20.cpp
@@ -331,12 +331,18 @@ private:
 	 * @return 0 on success, 1 on failure
 	 */
 	 int 			self_test();
+
+	/* this class does not allow copying */
+	L3GD20(const L3GD20&);
+	L3GD20 operator=(const L3GD20&);
 };
 
 L3GD20::L3GD20(int bus, const char* path, spi_dev_e device, enum Rotation rotation) :
 	SPI("L3GD20", path, bus, device, SPIDEV_MODE3, 11*1000*1000 /* will be rounded to 10.4 MHz, within margins for L3GD20 */),
+	_call{},
 	_call_interval(0),
 	_reports(nullptr),
+	_gyro_scale{},
 	_gyro_range_scale(0.0f),
 	_gyro_range_rad_s(0.0f),
 	_gyro_topic(-1),
@@ -1003,6 +1009,9 @@ void	info();
 
 /**
  * Start the driver.
+ *
+ * This function call only returns once the driver
+ * started or failed to detect the sensor.
  */
 void
 start(bool external_bus, enum Rotation rotation)
diff --git a/src/drivers/l3gd20/module.mk b/src/drivers/l3gd20/module.mk
index 23e77e8712..5630e7aeca 100644
--- a/src/drivers/l3gd20/module.mk
+++ b/src/drivers/l3gd20/module.mk
@@ -4,3 +4,7 @@
 
 MODULE_COMMAND	 = l3gd20
 SRCS		 = l3gd20.cpp
+
+MODULE_STACKSIZE	= 1200
+
+EXTRACXXFLAGS	= -Weffc++
diff --git a/src/drivers/lsm303d/lsm303d.cpp b/src/drivers/lsm303d/lsm303d.cpp
index 2750f8755e..6880cf0f87 100644
--- a/src/drivers/lsm303d/lsm303d.cpp
+++ b/src/drivers/lsm303d/lsm303d.cpp
@@ -462,6 +462,10 @@ private:
 	 * @return		OK if the value can be supported.
 	 */
 	int			mag_set_samplerate(unsigned frequency);
+
+	/* this class cannot be copied */
+	LSM303D(const LSM303D&);
+	LSM303D operator=(const LSM303D&);
 };
 
 /**
@@ -492,20 +496,28 @@ private:
 	void				measure();
 
 	void				measure_trampoline(void *arg);
+
+	/* this class does not allow copying due to ptr data members */
+	LSM303D_mag(const LSM303D_mag&);
+	LSM303D_mag operator=(const LSM303D_mag&);
 };
 
 
 LSM303D::LSM303D(int bus, const char* path, spi_dev_e device, enum Rotation rotation) :
 	SPI("LSM303D", path, bus, device, SPIDEV_MODE3, 11*1000*1000 /* will be rounded to 10.4 MHz, within safety margins for LSM303D */),
 	_mag(new LSM303D_mag(this)),
+	_accel_call{},
+	_mag_call{},
 	_call_accel_interval(0),
 	_call_mag_interval(0),
 	_accel_reports(nullptr),
 	_mag_reports(nullptr),
+	_accel_scale{},
 	_accel_range_m_s2(0.0f),
 	_accel_range_scale(0.0f),
 	_accel_samplerate(0),
 	_accel_onchip_filter_bandwith(0),
+	_mag_scale{},
 	_mag_range_ga(0.0f),
 	_mag_range_scale(0.0f),
 	_mag_samplerate(0),
@@ -527,6 +539,7 @@ LSM303D::LSM303D(int bus, const char* path, spi_dev_e device, enum Rotation rota
 	_reg7_expected(0),
 	_accel_log_fd(-1),
 	_accel_logging_enabled(false),
+	_last_extreme_us(0),
 	_last_log_us(0),
 	_last_log_sync_us(0),
 	_last_log_reg_us(0),
@@ -1829,6 +1842,9 @@ void	usage();
 
 /**
  * Start the driver.
+ *
+ * This function call only returns once the driver is
+ * up and running or failed to detect the sensor.
  */
 void
 start(bool external_bus, enum Rotation rotation)
diff --git a/src/drivers/lsm303d/module.mk b/src/drivers/lsm303d/module.mk
index e40f718c54..b4f3974f4d 100644
--- a/src/drivers/lsm303d/module.mk
+++ b/src/drivers/lsm303d/module.mk
@@ -5,4 +5,6 @@
 MODULE_COMMAND	 = lsm303d
 SRCS		 = lsm303d.cpp
 
+MODULE_STACKSIZE	= 1200
 
+EXTRACXXFLAGS	= -Weffc++
diff --git a/src/drivers/meas_airspeed/meas_airspeed.cpp b/src/drivers/meas_airspeed/meas_airspeed.cpp
index 07611f9039..6ab4377167 100644
--- a/src/drivers/meas_airspeed/meas_airspeed.cpp
+++ b/src/drivers/meas_airspeed/meas_airspeed.cpp
@@ -140,9 +140,9 @@ extern "C" __EXPORT int meas_airspeed_main(int argc, char *argv[]);
 MEASAirspeed::MEASAirspeed(int bus, int address, const char *path) : Airspeed(bus, address,
 	CONVERSION_INTERVAL, path),
 	_filter(MEAS_RATE, MEAS_DRIVER_FILTER_FREQ),
-	_t_system_power(-1)
+	_t_system_power(-1),
+	system_power{}
 {
-	memset(&system_power, 0, sizeof(system_power));
 }
 
 int
@@ -420,6 +420,9 @@ void	info();
 
 /**
  * Start the driver.
+ *
+ * This function call only returns once the driver is up and running
+ * or failed to detect the sensor.
  */
 void
 start(int i2c_bus)
diff --git a/src/drivers/meas_airspeed/module.mk b/src/drivers/meas_airspeed/module.mk
index fed4078b63..2a15b669f4 100644
--- a/src/drivers/meas_airspeed/module.mk
+++ b/src/drivers/meas_airspeed/module.mk
@@ -36,6 +36,9 @@
 #
 
 MODULE_COMMAND		= meas_airspeed
-MODULE_STACKSIZE	= 2048
 
 SRCS			= meas_airspeed.cpp
+
+MODULE_STACKSIZE	= 1200
+
+EXTRACXXFLAGS	= -Weffc++
diff --git a/src/drivers/mpu6000/module.mk b/src/drivers/mpu6000/module.mk
index c7d9cd3ef1..5b4893b127 100644
--- a/src/drivers/mpu6000/module.mk
+++ b/src/drivers/mpu6000/module.mk
@@ -37,7 +37,8 @@
 
 MODULE_COMMAND	= mpu6000
 
-# XXX seems excessive, check if 2048 is not sufficient
-MODULE_STACKSIZE	 = 4096
-
 SRCS		= mpu6000.cpp
+
+MODULE_STACKSIZE	= 1200
+
+EXTRACXXFLAGS	= -Weffc++
diff --git a/src/drivers/mpu6000/mpu6000.cpp b/src/drivers/mpu6000/mpu6000.cpp
index 09eec0caf3..6f5dae7adb 100644
--- a/src/drivers/mpu6000/mpu6000.cpp
+++ b/src/drivers/mpu6000/mpu6000.cpp
@@ -344,6 +344,9 @@ private:
 	*/
 	void _set_sample_rate(uint16_t desired_sample_rate_hz);
 
+	/* do not allow to copy this class due to pointer data members */
+	MPU6000(const MPU6000&);
+	MPU6000 operator=(const MPU6000&);
 };
 
 /**
@@ -371,6 +374,9 @@ private:
 	orb_id_t		_gyro_orb_id;
 	int			_gyro_class_instance;
 
+	/* do not allow to copy this class due to pointer data members */
+	MPU6000_gyro(const MPU6000_gyro&);
+	MPU6000_gyro operator=(const MPU6000_gyro&);
 };
 
 /** driver 'main' command */
@@ -380,14 +386,17 @@ MPU6000::MPU6000(int bus, const char *path_accel, const char *path_gyro, spi_dev
 	SPI("MPU6000", path_accel, bus, device, SPIDEV_MODE3, MPU6000_LOW_BUS_SPEED),
 	_gyro(new MPU6000_gyro(this, path_gyro)),
 	_product(0),
+	_call{},
 	_call_interval(0),
 	_accel_reports(nullptr),
+	_accel_scale{},
 	_accel_range_scale(0.0f),
 	_accel_range_m_s2(0.0f),
 	_accel_topic(-1),
 	_accel_orb_id(nullptr),
 	_accel_class_instance(-1),
 	_gyro_reports(nullptr),
+	_gyro_scale{},
 	_gyro_range_scale(0.0f),
 	_gyro_range_rad_s(0.0f),
 	_sample_rate(1000),
@@ -1466,6 +1475,9 @@ void	usage();
 
 /**
  * Start the driver.
+ *
+ * This function only returns if the driver is up and running
+ * or failed to detect the sensor.
  */
 void
 start(bool external_bus, enum Rotation rotation)
@@ -1536,7 +1548,7 @@ test(bool external_bus)
 	int fd = open(path_accel, O_RDONLY);
 
 	if (fd < 0)
-		err(1, "%s open failed (try 'mpu6000 start' if the driver is not running)",
+		err(1, "%s open failed (try 'mpu6000 start')",
 		    path_accel);
 
 	/* get the driver */
diff --git a/src/drivers/px4fmu/fmu.cpp b/src/drivers/px4fmu/fmu.cpp
index 8cc1141aa5..82977a032f 100644
--- a/src/drivers/px4fmu/fmu.cpp
+++ b/src/drivers/px4fmu/fmu.cpp
@@ -179,6 +179,9 @@ private:
 	uint32_t	gpio_read(void);
 	int		gpio_ioctl(file *filp, int cmd, unsigned long arg);
 
+	/* do not allow to copy due to ptr data members */
+	PX4FMU(const PX4FMU&);
+	PX4FMU operator=(const PX4FMU&);
 };
 
 const PX4FMU::GPIOConfig PX4FMU::_gpio_tab[] = {
@@ -242,6 +245,7 @@ PX4FMU::PX4FMU() :
 	_task(-1),
 	_armed_sub(-1),
 	_outputs_pub(-1),
+	_armed{},
 	_num_outputs(0),
 	_primary_pwm_device(false),
 	_task_should_exit(false),
@@ -252,6 +256,7 @@ PX4FMU::PX4FMU() :
 	_groups_subscribed(0),
 	_control_subs{-1},
 	_poll_fds_num(0),
+	_pwm_limit{},
 	_failsafe_pwm{0},
 	_disarmed_pwm{0},
 	_num_failsafe_set(0),
diff --git a/src/drivers/px4fmu/module.mk b/src/drivers/px4fmu/module.mk
index eeb59e1a1f..a60f1a434a 100644
--- a/src/drivers/px4fmu/module.mk
+++ b/src/drivers/px4fmu/module.mk
@@ -6,3 +6,5 @@ MODULE_COMMAND	 = fmu
 SRCS		 = fmu.cpp
 
 MODULE_STACKSIZE = 1200
+
+EXTRACXXFLAGS	= -Weffc++
diff --git a/src/drivers/px4io/module.mk b/src/drivers/px4io/module.mk
index c14f1f7836..5b838fb75e 100644
--- a/src/drivers/px4io/module.mk
+++ b/src/drivers/px4io/module.mk
@@ -46,3 +46,5 @@ SRCS			= px4io.cpp \
 INCLUDE_DIRS    += $(NUTTX_SRC)/arch/arm/src/stm32 $(NUTTX_SRC)/arch/arm/src/common
 
 MODULE_STACKSIZE = 1200
+
+EXTRACXXFLAGS	= -Weffc++
diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp
index 7d78b0d275..711674886c 100644
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@@ -453,6 +453,9 @@ private:
 	 */
 	void			io_handle_vservo(uint16_t vservo, uint16_t vrssi);
 
+	/* do not allow to copy this class due to ptr data members */
+	PX4IO(const PX4IO&);
+	PX4IO operator=(const PX4IO&);
 };
 
 namespace
@@ -496,6 +499,8 @@ PX4IO::PX4IO(device::Device *interface) :
 	_to_battery(0),
 	_to_servorail(0),
 	_to_safety(0),
+	_outputs{},
+	_servorail_status{},
 	_primary_pwm_device(false),
 	_lockdown_override(false),
 	_battery_amp_per_volt(90.0f / 5.0f), // this matches the 3DR current sensor
diff --git a/src/lib/mathlib/math/filter/LowPassFilter2p.hpp b/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
index 74cd5d78c0..4360651751 100644
--- a/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
+++ b/src/lib/mathlib/math/filter/LowPassFilter2p.hpp
@@ -46,10 +46,18 @@ class __EXPORT LowPassFilter2p
 {
 public:
     // constructor
-    LowPassFilter2p(float sample_freq, float cutoff_freq) {
+    LowPassFilter2p(float sample_freq, float cutoff_freq) : 
+        _cutoff_freq(cutoff_freq),
+        _a1(0.0f),
+        _a2(0.0f),
+        _b0(0.0f),
+        _b1(0.0f),
+        _b2(0.0f),
+        _delay_element_1(0.0f),
+        _delay_element_2(0.0f)
+    {
         // set initial parameters
         set_cutoff_frequency(sample_freq, cutoff_freq);
-        _delay_element_1 = _delay_element_2 = 0;
     }
 
     /**
diff --git a/src/modules/systemlib/mixer/mixer.h b/src/modules/systemlib/mixer/mixer.h
index 225570fa40..cdf60febc7 100644
--- a/src/modules/systemlib/mixer/mixer.h
+++ b/src/modules/systemlib/mixer/mixer.h
@@ -231,6 +231,10 @@ protected:
 	static const char *		skipline(const char *buf, unsigned &buflen);
 
 private:
+
+	/* do not allow to copy due to prt data members */
+	Mixer(const Mixer&);
+	Mixer& operator=(const Mixer&);
 };
 
 /**
@@ -307,6 +311,10 @@ public:
 
 private:
 	Mixer				*_first;	/**< linked list of mixers */
+
+	/* do not allow to copy due to pointer data members */
+	MixerGroup(const MixerGroup&);
+	MixerGroup operator=(const MixerGroup&);
 };
 
 /**
@@ -424,6 +432,10 @@ private:
 			mixer_scaler_s &scaler,
 			uint8_t &control_group,
 			uint8_t &control_index);
+
+	/* do not allow to copy due to ptr data members */
+	SimpleMixer(const SimpleMixer&);
+	SimpleMixer operator=(const SimpleMixer&);
 };
 
 /**
@@ -522,6 +534,9 @@ private:
 	unsigned			_rotor_count;
 	const Rotor			*_rotors;
 
+	/* do not allow to copy due to ptr data members */
+	MultirotorMixer(const MultirotorMixer&);
+	MultirotorMixer operator=(const MultirotorMixer&);
 };
 
 #endif