[stable/4.14.y PATCH 2/3] mmc: Fix null pointer dereference in mmc_init_request

[Raul E Rangel]

It is possible for queuedata to be cleared in mmc_cleanup_queue before
the request has been started. This will result in dereferencing a null
pointer.

Signed-off-by: Raul E Rangel <rran...@chromium.org>
---

 drivers/mmc/core/queue.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index d99fa4e63033c..bd7d521d5ad9d 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -159,8 +159,14 @@ static int mmc_init_request(struct request_queue *q, 
struct request *req,
 {
        struct mmc_queue_req *mq_rq = req_to_mmc_queue_req(req);
        struct mmc_queue *mq = q->queuedata;
-       struct mmc_card *card = mq->card;
-       struct mmc_host *host = card->host;
+       struct mmc_card *card;
+       struct mmc_host *host;
+
+       if (!mq)
+               return -ENODEV;
+
+       card = mq->card;
+       host = card->host;
 
        mq_rq->sg = mmc_alloc_sg(host->max_segs, gfp);
        if (!mq_rq->sg)
-- 
2.21.0.1020.gf2820cf01a-goog