The patch titled
rcu: Fix sign bug making rcu_random always return the same sequence
has been removed from the -mm tree. Its filename is
rcu-fix-sign-bug-making-rcu_random-always-return-the-same.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: rcu: Fix sign bug making rcu_random always return the same sequence
From: Josh Triplett <josht@xxxxxxxxxx>
rcu_random uses a counter rrs_count to occasionally mix data from
get_random_bytes into the state of its pseudorandom generator. However,
the rrs_counter gets declared as an unsigned long, and rcu_random checks
for --rrs_count < 0, so this code will never mix any real random data into
the state, and will thus always return the same sequence of random numbers.
Also, change the return value of rcu_random from long to unsigned long, to
avoid potential issues caused by the use of the % operator, which can
return negative values for negative left operands.
Signed-off-by: Josh Triplett <josh@xxxxxxxxxxxxxxx>
Acked-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/rcutorture.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN kernel/rcutorture.c~rcu-fix-sign-bug-making-rcu_random-always-return-the-same kernel/rcutorture.c
--- a/kernel/rcutorture.c~rcu-fix-sign-bug-making-rcu_random-always-return-the-same
+++ a/kernel/rcutorture.c
@@ -147,7 +147,7 @@ rcu_torture_free(struct rcu_torture *p)
struct rcu_random_state {
unsigned long rrs_state;
- unsigned long rrs_count;
+ long rrs_count;
};
#define RCU_RANDOM_MULT 39916801 /* prime */
@@ -160,7 +160,7 @@ struct rcu_random_state {
* Crude but fast random-number generator. Uses a linear congruential
* generator, with occasional help from get_random_bytes().
*/
-static long
+static unsigned long
rcu_random(struct rcu_random_state *rrsp)
{
long refresh;
_
Patches currently in -mm which might be from josht@xxxxxxxxxx are
origin.patch
-
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