diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 16f227b995e8..df45c265878e 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -38,6 +38,8 @@ static LIST_HEAD(rng_list);
 static DEFINE_MUTEX(rng_mutex);
 /* Protects rng read functions, data_avail, rng_buffer and rng_fillbuf */
 static DEFINE_MUTEX(reading_mutex);
+/* Keeps track of whoever is wait-reading it currently while holding reading_mutex. */
+static struct task_struct *current_waiting_reader;
 static int data_avail;
 static u8 *rng_buffer, *rng_fillbuf;
 static unsigned short current_quality;
@@ -208,6 +210,7 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
 	int err = 0;
 	int bytes_read, len;
 	struct hwrng *rng;
+	bool wait;
 
 	while (size) {
 		rng = get_current_rng();
@@ -225,9 +228,15 @@ static ssize_t rng_dev_read(struct file *filp, char __user *buf,
 			goto out_put;
 		}
 		if (!data_avail) {
+			wait = !(filp->f_flags & O_NONBLOCK);
+			if (wait && cmpxchg(&current_waiting_reader, NULL, current) != NULL) {
+				err = -EINTR;
+				goto out_unlock_reading;
+			}
 			bytes_read = rng_get_data(rng, rng_buffer,
-				rng_buffer_size(),
-				!(filp->f_flags & O_NONBLOCK));
+				rng_buffer_size(), wait);
+			if (wait && cmpxchg(&current_waiting_reader, current, NULL) != current)
+				synchronize_rcu();
 			if (bytes_read < 0) {
 				err = bytes_read;
 				goto out_unlock_reading;
@@ -513,8 +522,9 @@ static int hwrng_fillfn(void *unused)
 			break;
 
 		if (rc <= 0) {
-			pr_warn("hwrng: no data available\n");
-			msleep_interruptible(10000);
+			if (kthread_should_stop())
+				break;
+			schedule_timeout_interruptible(HZ * 10);
 			continue;
 		}
 
@@ -608,13 +618,21 @@ int hwrng_register(struct hwrng *rng)
 }
 EXPORT_SYMBOL_GPL(hwrng_register);
 
+#define UNREGISTERING_READER ((void *)~0UL)
+
 void hwrng_unregister(struct hwrng *rng)
 {
 	struct hwrng *old_rng, *new_rng;
+	struct task_struct *waiting_reader;
 	int err;
 
 	mutex_lock(&rng_mutex);
 
+	rcu_read_lock();
+	waiting_reader = xchg(&current_waiting_reader, UNREGISTERING_READER);
+	if (waiting_reader && waiting_reader != UNREGISTERING_READER)
+		set_notify_signal(waiting_reader);
+	rcu_read_unlock();
 	old_rng = current_rng;
 	list_del(&rng->list);
 	if (current_rng == rng) {
@@ -640,6 +658,10 @@ void hwrng_unregister(struct hwrng *rng)
 	}
 
 	wait_for_completion(&rng->cleanup_done);
+
+	mutex_lock(&rng_mutex);
+	cmpxchg(&current_waiting_reader, UNREGISTERING_READER, NULL);
+	mutex_unlock(&rng_mutex);
 }
 EXPORT_SYMBOL_GPL(hwrng_unregister);
 
diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c
index cb5414265a9b..8980dc36509e 100644
--- a/drivers/net/wireless/ath/ath9k/rng.c
+++ b/drivers/net/wireless/ath/ath9k/rng.c
@@ -52,18 +52,13 @@ static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size)
 	return j << 2;
 }
 
-static u32 ath9k_rng_delay_get(u32 fail_stats)
+static unsigned long ath9k_rng_delay_get(u32 fail_stats)
 {
-	u32 delay;
-
 	if (fail_stats < 100)
-		delay = 10;
+		return HZ / 100;
 	else if (fail_stats < 105)
-		delay = 1000;
-	else
-		delay = 10000;
-
-	return delay;
+		return HZ;
+	return HZ * 10;
 }
 
 static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
@@ -80,10 +75,10 @@ static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
 			bytes_read += max & 3UL;
 			memzero_explicit(&word, sizeof(word));
 		}
-		if (!wait || !max || likely(bytes_read) || fail_stats > 110)
+		if (!wait || !max || likely(bytes_read) || fail_stats > 110 ||
+		    ((current->flags & PF_KTHREAD) && kthread_should_stop()) ||
+		    schedule_timeout_interruptible(ath9k_rng_delay_get(++fail_stats)))
 			break;
-
-		msleep_interruptible(ath9k_rng_delay_get(++fail_stats));
 	}
 
 	if (wait && !bytes_read && max)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index da0bf6fe9ecd..d65a5eb9a65e 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4284,6 +4284,7 @@ int wake_up_state(struct task_struct *p, unsigned int state)
 {
 	return try_to_wake_up(p, state, 0);
 }
+EXPORT_SYMBOL(wake_up_state);
 
 /*
  * Perform scheduler related setup for a newly forked process p.
