[MTD] fix use after free in register_mtd_blktrans

Reported-by: Dan Carpenter <error27@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 1409f01..4109e0b 100644 (file)
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -382,11 +382,12 @@ int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
        tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
                        "%sd", tr->name);
        if (IS_ERR(tr->blkcore_priv->thread)) {
+               int ret = PTR_ERR(tr->blkcore_priv->thread);
                blk_cleanup_queue(tr->blkcore_priv->rq);
                unregister_blkdev(tr->major, tr->name);
                kfree(tr->blkcore_priv);
                mutex_unlock(&mtd_table_mutex);
-               return PTR_ERR(tr->blkcore_priv->thread);
+               return ret;
        }
 
        INIT_LIST_HEAD(&tr->devs);