A kernel with enabled lockdep complains about the wrong usage of
rcu_dereference() under a rcu_read_lock_bh() protected region.

  ===============================
  [ INFO: suspicious RCU usage. ]
  3.13.0-rc1+ #126 Not tainted
  -------------------------------
  linux/kernel/padata.c:115 suspicious rcu_dereference_check() usage!

  other info that might help us debug this:

  rcu_scheduler_active = 1, debug_locks = 1
  1 lock held by cryptomgr_test/153:
   #0:  (rcu_read_lock_bh){.+....}, at: [<ffffffff8115c235>] 
padata_do_parallel+0x5/0x270

Fix that by using rcu_dereference_bh() instead.

Signed-off-by: Mathias Krause <mini...@googlemail.com>
Cc: Steffen Klassert <steffen.klass...@secunet.com>
---
 kernel/padata.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/padata.c b/kernel/padata.c
index 2abd25d79c..161402f0b5 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -112,7 +112,7 @@ int padata_do_parallel(struct padata_instance *pinst,
 
        rcu_read_lock_bh();
 
-       pd = rcu_dereference(pinst->pd);
+       pd = rcu_dereference_bh(pinst->pd);
 
        err = -EINVAL;
        if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
-- 
1.7.10.4

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