The major/minor of a hidden gendisk is not propagated to the block device because it is never registered using bdev_add. But the lack of bd_dev also causes the dynamic major minor number not to be freed. Assign bd_dev manually to ensure the dynamic major minor gets freed. Based on a patch by Keith Busch. Fixes: 8ddcd653257c ("block: introduce GENHD_FL_HIDDEN") Reported-by: Daniel Wagner <dwagner@xxxxxxx> Signed-off-by: Christoph Hellwig <hch@xxxxxx> Tested-by: Daniel Wagner <dwagner@xxxxxxx> --- block/genhd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/block/genhd.c b/block/genhd.c index 514395361d7c5..17b33c62423df 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -507,6 +507,13 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, */ dev_set_uevent_suppress(ddev, 0); disk_uevent(disk, KOBJ_ADD); + } else { + /* + * Even if the block_device for a hidden gendisk is not + * registered, it needs to have a valid bd_dev so that the + * freeing of the dynamic major works. + */ + disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor); } disk_update_readahead(disk); -- 2.30.2