1 files changed, 4 insertions, 1 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3c7b537bf908..545b8d4c829d 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2772,8 +2772,11 @@ static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
         smp_wmb();
         cic->key = cfqd_dead_key(cfqd);
 
-        if (ioc->ioc_data == cic)
+        if (rcu_dereference(ioc->ioc_data) == cic) {
+                spin_lock(&ioc->lock);
                 rcu_assign_pointer(ioc->ioc_data, NULL);
+                spin_unlock(&ioc->lock);
+        }
 
         if (cic->cfqq[BLK_RW_ASYNC]) {
                 cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);