[PATCH] char: random: casting prevents missing calculations

From: Karim Eshapa
Date: Sun May 07 2017 - 18:10:46 EST


Cast (long)jiffies and (long)state->last_time beacause
they tends to unsigned long. may cause a problem specially
when comparison happens (< 0).

Signed-off-by: Karim Eshapa <karim.eshapa@xxxxxxxxx>
---
drivers/char/random.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 0ab0249..f685e78 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1012,7 +1012,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)

preempt_disable();

- sample.jiffies = jiffies;
+ sample.jiffies = (long)jiffies;
sample.cycles = random_get_entropy();
sample.num = num;
r = &input_pool;
@@ -1025,7 +1025,7 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
*/

if (!state->dont_count_entropy) {
- delta = sample.jiffies - state->last_time;
+ delta = sample.jiffies - (long)state->last_time;
state->last_time = sample.jiffies;

delta2 = delta - state->last_delta;
--
2.7.4