The patch titled
rcu: Fix sign bug making rcu_random always return the same sequence
has been added to the -mm tree. Its filename is
rcu-fix-sign-bug-making-rcu_random-always-return-the-same.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
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
xfs-add-lock-annotations-to-xfs_trans_update_ail-and-xfs_trans_delete_ail.patch
efi-add-lock-annotations-for-efi_call_phys_prelog-and-efi_call_phys_epilog.patch
mbcache-add-lock-annotation-for-__mb_cache_entry_release_unlock.patch
afs-add-lock-annotations-to-afs_proc_cell_servers_startstop.patch
fuse-add-lock-annotations-to-request_end-and-fuse_read_interrupt.patch
hugetlbfs-add-lock-annotation-to-hugetlbfs_forget_inode.patch
jbd-add-lock-annotation-to-jbd_sync_bh.patch
fs-add-lock-annotation-to-grab_super.patch
rcu-add-lock-annotations-to-rcu_bh_torture_read_lockunlock.patch
timer-add-lock-annotation-to-lock_timer_base.patch
nfsd-add-lock-annotations-to-e_start-and-e_stop.patch
rcu-add-module_author-to-rcutorture-module.patch
rcu-fix-incorrect-description-of-default-for-rcutorture.patch
rcu-mention-rcu_bh-in-description-of-rcutortures.patch
rcu-avoid-kthread_stop-on-invalid-pointer-if-rcutorture.patch
rcu-fix-sign-bug-making-rcu_random-always-return-the-same.patch
-
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