From: Yang Yang <yang.y...@vivo.com>

[ Upstream commit 47ce030b7ac5a5259a9a5919f230b52497afc31a ]

blk_exit_queue will free elevator_data, while blk_mq_run_work_fn
will access it. Move cancel of hctx->run_work to the front of
blk_exit_queue to avoid use-after-free.

Fixes: 1b97871b501f ("blk-mq: move cancel of hctx->run_work into 
blk_mq_hw_sysfs_release")
Signed-off-by: Yang Yang <yang.y...@vivo.com>
Reviewed-by: Ming Lei <ming....@redhat.com>
Signed-off-by: Jens Axboe <ax...@kernel.dk>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 block/blk-mq-sysfs.c | 2 --
 block/blk-sysfs.c    | 9 ++++++++-
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 062229395a507..7b52e7657b2d1 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -36,8 +36,6 @@ static void blk_mq_hw_sysfs_release(struct kobject *kobj)
        struct blk_mq_hw_ctx *hctx = container_of(kobj, struct blk_mq_hw_ctx,
                                                  kobj);
 
-       cancel_delayed_work_sync(&hctx->run_work);
-
        if (hctx->flags & BLK_MQ_F_BLOCKING)
                cleanup_srcu_struct(hctx->srcu);
        blk_free_flush_queue(hctx->fq);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 7dda709f3ccb6..8c6bafc801dd9 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -934,9 +934,16 @@ static void blk_release_queue(struct kobject *kobj)
 
        blk_free_queue_stats(q->stats);
 
-       if (queue_is_mq(q))
+       if (queue_is_mq(q)) {
+               struct blk_mq_hw_ctx *hctx;
+               int i;
+
                cancel_delayed_work_sync(&q->requeue_work);
 
+               queue_for_each_hw_ctx(q, hctx, i)
+                       cancel_delayed_work_sync(&hctx->run_work);
+       }
+
        blk_exit_queue(q);
 
        blk_queue_free_zone_bitmaps(q);
-- 
2.25.1



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