diff --git a/drivers/net/wireless/ath/ath5k/debug.c b/drivers/net/wireless/ath/ath5k/debug.c
index 9d00dab666a8de1b52aca10190f0b1db542d4f91..b8d031ae63c2f8019a0c997295e52f9b2b01b46c 100644
--- a/drivers/net/wireless/ath/ath5k/debug.c
+++ b/drivers/net/wireless/ath/ath5k/debug.c
@@ -245,9 +245,11 @@ static ssize_t write_file_beacon(struct file *file,
 	struct ath5k_hw *ah = file->private_data;
 	char buf[20];
 
-	if (copy_from_user(buf, userbuf, min(count, sizeof(buf))))
+	count = min_t(size_t, count, sizeof(buf) - 1);
+	if (copy_from_user(buf, userbuf, count))
 		return -EFAULT;
 
+	buf[count] = '\0';
 	if (strncmp(buf, "disable", 7) == 0) {
 		AR5K_REG_DISABLE_BITS(ah, AR5K_BEACON, AR5K_BEACON_ENABLE);
 		pr_info("debugfs disable beacons\n");
@@ -345,9 +347,11 @@ static ssize_t write_file_debug(struct file *file,
 	unsigned int i;
 	char buf[20];
 
-	if (copy_from_user(buf, userbuf, min(count, sizeof(buf))))
+	count = min_t(size_t, count, sizeof(buf) - 1);
+	if (copy_from_user(buf, userbuf, count))
 		return -EFAULT;
 
+	buf[count] = '\0';
 	for (i = 0; i < ARRAY_SIZE(dbg_info); i++) {
 		if (strncmp(buf, dbg_info[i].name,
 					strlen(dbg_info[i].name)) == 0) {
@@ -448,9 +452,11 @@ static ssize_t write_file_antenna(struct file *file,
 	unsigned int i;
 	char buf[20];
 
-	if (copy_from_user(buf, userbuf, min(count, sizeof(buf))))
+	count = min_t(size_t, count, sizeof(buf) - 1);
+	if (copy_from_user(buf, userbuf, count))
 		return -EFAULT;
 
+	buf[count] = '\0';
 	if (strncmp(buf, "diversity", 9) == 0) {
 		ath5k_hw_set_antenna_mode(ah, AR5K_ANTMODE_DEFAULT);
 		pr_info("debug: enable diversity\n");
@@ -619,9 +625,11 @@ static ssize_t write_file_frameerrors(struct file *file,
 	struct ath5k_statistics *st = &ah->stats;
 	char buf[20];
 
-	if (copy_from_user(buf, userbuf, min(count, sizeof(buf))))
+	count = min_t(size_t, count, sizeof(buf) - 1);
+	if (copy_from_user(buf, userbuf, count))
 		return -EFAULT;
 
+	buf[count] = '\0';
 	if (strncmp(buf, "clear", 5) == 0) {
 		st->rxerr_crc = 0;
 		st->rxerr_phy = 0;
@@ -766,9 +774,11 @@ static ssize_t write_file_ani(struct file *file,
 	struct ath5k_hw *ah = file->private_data;
 	char buf[20];
 
-	if (copy_from_user(buf, userbuf, min(count, sizeof(buf))))
+	count = min_t(size_t, count, sizeof(buf) - 1);
+	if (copy_from_user(buf, userbuf, count))
 		return -EFAULT;
 
+	buf[count] = '\0';
 	if (strncmp(buf, "sens-low", 8) == 0) {
 		ath5k_ani_init(ah, ATH5K_ANI_MODE_MANUAL_HIGH);
 	} else if (strncmp(buf, "sens-high", 9) == 0) {
@@ -862,9 +872,11 @@ static ssize_t write_file_queue(struct file *file,
 	struct ath5k_hw *ah = file->private_data;
 	char buf[20];
 
-	if (copy_from_user(buf, userbuf, min(count, sizeof(buf))))
+	count = min_t(size_t, count, sizeof(buf) - 1);
+	if (copy_from_user(buf, userbuf, count))
 		return -EFAULT;
 
+	buf[count] = '\0';
 	if (strncmp(buf, "start", 5) == 0)
 		ieee80211_wake_queues(ah->hw);
 	else if (strncmp(buf, "stop", 4) == 0)