Merge tag 'block-6.2-2023-02-03' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:
 "A bit bigger than I'd like at this point, but mostly a bunch of little
  fixes. In detail:

   - NVMe pull request via Christoph:
       - Fix a missing queue put in nvmet_fc_ls_create_association
         (Amit Engel)
       - Clear queue pointers on tag_set initialization failure
         (Maurizio Lombardi)
       - Use workqueue dedicated to authentication (Shin'ichiro
         Kawasaki)

   - Fix for an overflow in ublk (Liu)

   - Fix for leaking a queue reference in block cgroups (Ming)

   - Fix for a use-after-free in BFQ (Yu)"

* tag 'block-6.2-2023-02-03' of git://git.kernel.dk/linux:
  blk-cgroup: don't update io stat for root cgroup
  nvme-auth: use workqueue dedicated to authentication
  nvme: clear the request_queue pointers on failure in nvme_alloc_io_tag_set
  nvme: clear the request_queue pointers on failure in nvme_alloc_admin_tag_set
  nvme-fc: fix a missing queue put in nvmet_fc_ls_create_association
  block: Fix the blk_mq_destroy_queue() documentation
  block: ublk: extending queue_size to fix overflow
  block, bfq: fix uaf for bfqq in bic_set_bfqq()

4 files changed, 11 insertions, 4 deletions

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 7d9b15f0dbd5..0fbde0fc0628 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -769,8 +769,8 @@ static void __bfq_bic_change_cgroup(struct bfq_data *bfqd,
 				 * request from the old cgroup.
 				 */
 				bfq_put_cooperator(sync_bfqq);
-				bfq_release_process_ref(bfqd, sync_bfqq);
 				bic_set_bfqq(bic, NULL, true);
+				bfq_release_process_ref(bfqd, sync_bfqq);
 			}
 		}
 	}
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index ccf2204477a5..380e9bda2e57 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -5425,9 +5425,11 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio)
 
 	bfqq = bic_to_bfqq(bic, false);
 	if (bfqq) {
-		bfq_release_process_ref(bfqd, bfqq);
+		struct bfq_queue *old_bfqq = bfqq;
+
 		bfqq = bfq_get_queue(bfqd, bio, false, bic, true);
 		bic_set_bfqq(bic, bfqq, false);
+		bfq_release_process_ref(bfqd, old_bfqq);
 	}
 
 	bfqq = bic_to_bfqq(bic, true);
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 4c94a6560f62..9ac1efb053e0 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -2001,6 +2001,10 @@ void blk_cgroup_bio_start(struct bio *bio)
 	struct blkg_iostat_set *bis;
 	unsigned long flags;
 
+	/* Root-level stats are sourced from system-wide IO stats */
+	if (!cgroup_parent(blkcg->css.cgroup))
+		return;
+
 	cpu = get_cpu();
 	bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu);
 	flags = u64_stats_update_begin_irqsave(&bis->sync);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9d463f7563bc..9c8dc70020bc 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4069,8 +4069,9 @@ EXPORT_SYMBOL(blk_mq_init_queue);
  * blk_mq_destroy_queue - shutdown a request queue
  * @q: request queue to shutdown
  *
- * This shuts down a request queue allocated by blk_mq_init_queue() and drops
- * the initial reference.  All future requests will failed with -ENODEV.
+ * This shuts down a request queue allocated by blk_mq_init_queue(). All future
+ * requests will be failed with -ENODEV. The caller is responsible for dropping
+ * the reference from blk_mq_init_queue() by calling blk_put_queue().
  *
  * Context: can sleep
  */