[PATCH 5/5] random: properly align get_random_int_hash

From: Theodore Ts'o
Date: Mon May 30 2016 - 01:41:38 EST

From: Eric Biggers <ebiggers3@xxxxxxxxx>

get_random_long() reads from the get_random_int_hash array using an
unsigned long pointer. For this code to be guaranteed correct on all
architectures, the array must be aligned to an unsigned long boundary.

Signed-off-by: Eric Biggers <ebiggers3@xxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
drivers/char/random.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 860862f..90fb569 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2033,13 +2033,15 @@ int random_int_secret_init(void)
return 0;

+static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash)
+ __aligned(sizeof(unsigned long));
* Get a random word for internal kernel use only. Similar to urandom but
* with the goal of minimal entropy pool depletion. As a result, the random
* value is not cryptographically secure but for several uses the cost of
* depleting entropy is too high
-static DEFINE_PER_CPU(__u32 [MD5_DIGEST_WORDS], get_random_int_hash);
unsigned int get_random_int(void)
__u32 *hash;