crypto: pcrypt - Fix wrong usage of rcu_dereference()

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/crypto/pcrypt.c:81 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: [<ffffffff812c8075>] pcrypt_do_parallel.isra.2+0x5/0x200

Fix that by using rcu_dereference_bh() instead.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
index f8c920cafe639c8451349e15b3f1e22e19da80e4..309d345ead9582896bde8c5f5c170bf5d0315f66 100644 (file)
--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -78,7 +78,7 @@ static int pcrypt_do_parallel(struct padata_priv *padata, unsigned int *cb_cpu,
        cpu = *cb_cpu;
 
        rcu_read_lock_bh();
-       cpumask = rcu_dereference(pcrypt->cb_cpumask);
+       cpumask = rcu_dereference_bh(pcrypt->cb_cpumask);
        if (cpumask_test_cpu(cpu, cpumask->mask))
                        goto out;