CVE-2022-49377

Description

In the Linux kernel, the following vulnerability has been resolved: blk-mq: dont touch ->tagset in blk_mq_get_sq_hctx blk_mq_run_hw_queues() could be run when there isnt queued request and after queue is cleaned up, at that time tagset is freed, because tagset lifetime is covered by driver, and often freed after blk_cleanup_queue() returns. So dont touch ->tagset for figuring out current default hctx by the mapping built in request queue, so use-after-free on tagset can be avoided. Meantime this way should be fast than retrieving mapping from tagset.