diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index bb000fc..ec614f5 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -1101,6 +1101,11 @@ static int check_mtp_mode(void)
 	int mtp_flag = 0;
 
 	fd = fopen("/sys/class/android_usb/android0/functions", "r");
+	if (!fd) {
+		printf("failed to open /sys/class/android_usb/android0/functions\n");
+		return 0;
+	}
+
 	while (fgets(buffer, 128, fd)) {
 		if (strstr(buffer, "mtp") != NULL) {
 			mtp_flag = 1;
@@ -1118,6 +1123,10 @@ static int check_usb_status(void)
 	int usb_status = 0;
 
 	fp = fopen("/sys/class/android_usb/android0/state", "r");
+	if (!fp) {
+		printf("failed to open /sys/class/android_usb/android0/state\n");
+		return 0;
+		}
 	while(fgets(buffer, 16, fp)) {
 		if (strstr(buffer, "CONFIGURED") != NULL) {
 			usb_status = 1;
@@ -1133,6 +1142,10 @@ static void get_usb_state(char *usb_state)
 	FILE *fp;
 
 	fp = fopen("/sys/class/android_usb/android0/state", "r");
+	if (!fp) {
+		printf("failed to open /sys/class/android_usb/android0/state\n");
+		return;
+		}
 	fgets(usb_state, 16, fp);
 	fclose(fp);
 	return;