diff --git a/src/aio/aio.c b/src/aio/aio.c
index de92d76..791cf46 100644
--- a/src/aio/aio.c
+++ b/src/aio/aio.c
@@ -37,6 +37,11 @@ static int raw_bits;
 static mraa_result_t
 aio_get_valid_fp(mraa_aio_context dev)
 {
+    if (dev == NULL) {
+        syslog(LOG_ERR, "aio: get_valid_fp: context is invalid");
+        return MRAA_ERROR_INVALID_HANDLE;
+    }
+
     if (IS_FUNC_DEFINED(dev, aio_get_valid_fp)) {
         return dev->advance_func->aio_get_valid_fp(dev);
     }
diff --git a/src/gpio/gpio.c b/src/gpio/gpio.c
index 7803881..5283937 100644
--- a/src/gpio/gpio.c
+++ b/src/gpio/gpio.c
@@ -238,6 +238,11 @@ mraa_gpio_wait_interrupt(int fd
 static void*
 mraa_gpio_interrupt_handler(void* arg)
 {
+    if (arg == NULL) {
+        syslog(LOG_ERR, "gpio: interrupt_handler: context is invalid");
+        return NULL;
+    }
+
     mraa_gpio_context dev = (mraa_gpio_context) arg;
     int fp = -1;
     mraa_result_t ret;
diff --git a/src/iio/iio.c b/src/iio/iio.c
index 9163f4a..b55eb25 100644
--- a/src/iio/iio.c
+++ b/src/iio/iio.c
@@ -465,7 +465,7 @@ mraa_iio_event_poll(mraa_iio_context dev, struct iio_event_data* data)
     if (ret == -1 || event_fd == -1)
         return MRAA_ERROR_UNSPECIFIED;
 
-    ret = read(event_fd, data, sizeof(struct iio_event_data));
+    read(event_fd, data, sizeof(struct iio_event_data));
 
     close(event_fd);
     return MRAA_SUCCESS;