On Thu, Feb 23, 2017 at 11:22:03AM -0800, Dan Williams wrote: > If device_add() fails, cleanup the cdev. Otherwise, we leak a kobj_map() > with a stale device number. > > Fixes: ba09c01d2fa8 ("dax: convert to the cdev api") > Cc: <stable(a)vger.kernel.org&gt; > Cc: Logan Gunthorpe <logang(a)deltatee.com&gt; > Reported-by: Jason Gunthorpe <jgunthorpe(a)obsidianresearch.com&gt; > Signed-off-by: Dan Williams <dan.j.williams(a)intel.com&gt; > drivers/dax/dax.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c > index ed758b74ddf0..0f8008dd0b0c 100644 > +++ b/drivers/dax/dax.c > @@ -724,6 +724,7 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region, > dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id); > rc = device_add(dev); > if (rc) { > + cdev_del(&dax_dev->cdev); This probably should call into unregister_dax_dev and just skip the device_unregister part. Once cdev_add returns it is possible for a mmap to have been created, so cleanup after that point has to go through all the other unregister_dax_dev steps.