Patch "random: initialize the non-blocking pool via add_hwgenerator_randomness()" has been added to the 4.4-stable tree

Patch "random: initialize the non-blocking pool via add_hwgenerator_randomness()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    random: initialize the non-blocking pool via add_hwgenerator_randomness()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     random-initialize-the-non-blocking-pool-via-add_hwgenerator_randomness.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 3371f3da08cff4b75c1f2dce742d460539d6566d Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Sun, 12 Jun 2016 18:11:51 -0400
Subject: random: initialize the non-blocking pool via add_hwgenerator_randomness()

From: Theodore Ts'o <tytso@mit.edu>

commit 3371f3da08cff4b75c1f2dce742d460539d6566d upstream.

If we have a hardware RNG and are using the in-kernel rngd, we should
use this to initialize the non-blocking pool so that getrandom(2)
doesn't block unnecessarily.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/char/random.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1849,12 +1849,18 @@ void add_hwgenerator_randomness(const ch
 {
 	struct entropy_store *poolp = &input_pool;
 
-	/* Suspend writing if we're above the trickle threshold.
-	 * We'll be woken up again once below random_write_wakeup_thresh,
-	 * or when the calling thread is about to terminate.
-	 */
-	wait_event_interruptible(random_write_wait, kthread_should_stop() ||
+	if (unlikely(nonblocking_pool.initialized == 0))
+		poolp = &nonblocking_pool;
+	else {
+		/* Suspend writing if we're above the trickle
+		 * threshold.  We'll be woken up again once below
+		 * random_write_wakeup_thresh, or when the calling
+		 * thread is about to terminate.
+		 */
+		wait_event_interruptible(random_write_wait,
+					 kthread_should_stop() ||
 			ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits);
+	}
 	mix_pool_bytes(poolp, buffer, count);
 	credit_entropy_bits(poolp, entropy);
 }


Patches currently in stable-queue which might be from tytso@mit.edu are

queue-4.4/random-print-a-warning-for-the-first-ten-uninitialized-random-users.patch
queue-4.4/random-properly-align-get_random_int_hash.patch
queue-4.4/random-initialize-the-non-blocking-pool-via-add_hwgenerator_randomness.patch
queue-4.4/random-add-interrupt-callback-to-vmbus-irq-handler.patch
queue-4.4/jbd2-make-journal-y2038-safe.patch