1 files changed, 6 insertions, 2 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f3799432676d..ae21919f15e1 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2773,11 +2773,14 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
         smp_wmb();
         cic->key = cfqd_dead_key(cfqd);
 
+        rcu_read_lock();
         if (rcu_dereference(ioc->ioc_data) == cic) {
+                rcu_read_unlock();
                 spin_lock(&ioc->lock);
                 rcu_assign_pointer(ioc->ioc_data, NULL);
                 spin_unlock(&ioc->lock);
-        }
+        } else
+                rcu_read_unlock();
 
         if (cic->cfqq[BLK_RW_ASYNC]) {
                 cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
@@ -3084,7 +3087,8 @@ cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc,
 
         spin_lock_irqsave(&ioc->lock, flags);
 
-        BUG_ON(ioc->ioc_data == cic);
+        BUG_ON(rcu_dereference_check(ioc->ioc_data,
+                lockdep_is_held(&ioc->lock)) == cic);
 
         radix_tree_delete(&ioc->radix_root, cfqd->cic_index);
         hlist_del_rcu(&cic->cic_list);