On Wed, Nov 03, 2021 at 05:21:45AM -0700, Luis Chamberlain wrote:

del_gendisk() is not required if the disk has not been added.
On kernels prior to commit 40b3a52ffc5bc3 ("block: add a sanity
check for a live disk in del_gendisk") it is mandatory to not
call del_gendisk() if the underlying device has not been through
device_add().

And even with the sanity check is it wrong, and will trigger a WARN_ON.
So maybe this commit log could use a little update?

With that fixed I think this should go into 5.16 and -stable.

Reviewed-by: Christoph Hellwig <hch@lst.de>