Revert "blk-mq: fix hctx/ctx kobject use-after-free"

This reverts commit 76d697d10769048e5721510100bf3a9413a56385.

The commit 76d697d10769048 causes general protection fault
reported from Bart Van Assche:

	https://lkml.org/lkml/2015/1/28/334

Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9ee3b87c4498..2f95747c287e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1641,8 +1641,10 @@ static void blk_mq_free_hw_queues(struct request_queue *q,
         struct blk_mq_hw_ctx *hctx;
         unsigned int i;
 
-        queue_for_each_hw_ctx(q, hctx, i)
+        queue_for_each_hw_ctx(q, hctx, i) {
                 free_cpumask_var(hctx->cpumask);
+                kfree(hctx);
+        }
 }
 
 static int blk_mq_init_hctx(struct request_queue *q,
@@ -2000,9 +2002,11 @@ void blk_mq_free_queue(struct request_queue *q)
 
         percpu_ref_exit(&q->mq_usage_counter);
 
+        free_percpu(q->queue_ctx);
         kfree(q->queue_hw_ctx);
         kfree(q->mq_map);
 
+        q->queue_ctx = NULL;
         q->queue_hw_ctx = NULL;
         q->mq_map = NULL;