Merge: block: four CVE fixes

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6358

JIRA: https://issues.redhat.com/browse/RHEL-75869
CVE: CVE-2024-56672

JIRA: https://issues.redhat.com/browse/RHEL-77216
CVE: CVE-2025-21671

JIRA: https://issues.redhat.com/browse/RHEL-77310
CVE: CVE-2025-21631

JIRA: https://issues.redhat.com/browse/RHEL-75854
CVE: CVE-2024-53170

Signed-off-by: Ming Lei <ming.lei@redhat.com>

Approved-by: Jeff Moyer <jmoyer@redhat.com>
Approved-by: Maurizio Lombardi <mlombard@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

block/bfq-iosched.c

@@ -6844,16 +6844,24 @@ static struct bfq_queue *bfq_waker_bfqq(struct bfq_queue *bfqq)
 		if (new_bfqq == waker_bfqq) {
 			/*
 			 * If waker_bfqq is in the merge chain, and current
-			 * is the only procress.
+			 * is the only process, waker_bfqq can be freed.
 			 */
 			if (bfqq_process_refs(waker_bfqq) == 1)
 				return NULL;
-			break;
+
+			return waker_bfqq;
 		}
 
 		new_bfqq = new_bfqq->new_bfqq;
 	}
 
+	/*
+	 * If waker_bfqq is not in the merge chain, and it's procress reference
+	 * is 0, waker_bfqq can be freed.
+	 */
+	if (bfqq_process_refs(waker_bfqq) == 0)
+		return NULL;
+
 	return waker_bfqq;
 }
 

block/blk-cgroup.c

@@ -1325,10 +1325,14 @@ void blkcg_unpin_online(struct cgroup_subsys_state *blkcg_css)
 	struct blkcg *blkcg = css_to_blkcg(blkcg_css);
 
 	do {
+		struct blkcg *parent;
+
 		if (!refcount_dec_and_test(&blkcg->online_pin))
 			break;
+
+		parent = blkcg_parent(blkcg);
 		blkcg_destroy_blkgs(blkcg);
-		blkcg = blkcg_parent(blkcg);
+		blkcg = parent;
 	} while (blkcg);
 }
 

block/blk-sysfs.c

@@ -800,10 +800,8 @@ int blk_register_queue(struct gendisk *disk)
 	 * faster to shut down and is made fully functional here as
 	 * request_queues for non-existent devices never get registered.
 	 */
-	if (!blk_queue_init_done(q)) {
-		blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
-		percpu_ref_switch_to_percpu(&q->q_usage_counter);
-	}
+	blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
+	percpu_ref_switch_to_percpu(&q->q_usage_counter);
 
 	return ret;
 

block/genhd.c

@@ -706,13 +706,10 @@ void del_gendisk(struct gendisk *disk)
 	 * If the disk does not own the queue, allow using passthrough requests
 	 * again.  Else leave the queue frozen to fail all I/O.
 	 */
-	if (!test_bit(GD_OWNS_QUEUE, &disk->state)) {
-		blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
+	if (!test_bit(GD_OWNS_QUEUE, &disk->state))
 		__blk_mq_unfreeze_queue(q, true);
-	} else {
-		if (queue_is_mq(q))
-			blk_mq_exit_queue(q);
-	}
+	else if (queue_is_mq(q))
+		blk_mq_exit_queue(q);
 }
 EXPORT_SYMBOL(del_gendisk);
 

drivers/block/zram/zram_drv.c

@@ -1223,12 +1223,16 @@ static void zram_meta_free(struct zram *zram, u64 disksize)
 	size_t num_pages = disksize >> PAGE_SHIFT;
 	size_t index;
 
+	if (!zram->table)
+		return;
+
 	/* Free all pages that are still in this zram device */
 	for (index = 0; index < num_pages; index++)
 		zram_free_page(zram, index);
 
 	zs_destroy_pool(zram->mem_pool);
 	vfree(zram->table);
+	zram->table = NULL;
 }
 
 static bool zram_meta_alloc(struct zram *zram, u64 disksize)
@@ -1243,6 +1247,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
 	zram->mem_pool = zs_create_pool(zram->disk->disk_name);
 	if (!zram->mem_pool) {
 		vfree(zram->table);
+		zram->table = NULL;
 		return false;
 	}
 
@@ -2002,11 +2007,6 @@ static void zram_reset_device(struct zram *zram)
 
 	zram->limit_pages = 0;
 
-	if (!init_done(zram)) {
-		up_write(&zram->init_lock);
-		return;
-	}
-
 	set_capacity_and_notify(zram->disk, 0);
 	part_stat_set_all(zram->disk->part0, 0);