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| author | Dan Williams <dan.j.williams@intel.com> | 2017-03-17 21:48:09 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-20 15:31:02 +0300 |
| commit | e1a19ef5291902ec413abdd4037ee27bf6a35594 (patch) | |
| tree | 8874a0d918594a38ae652305af3a304c70bc31ff | |
| parent | 81845f52017951b6623618d68f79a7530073f2d0 (diff) | |
| download | linux-e1a19ef5291902ec413abdd4037ee27bf6a35594.tar.xz | |
device-dax: fix cdev leak
commit ed01e50acdd3e4a640cf9ebd28a7e810c3ceca97 upstream.
If device_add() fails, cleanup the cdev. Otherwise, we leak a kobj_map()
with a stale device number.
As Jason points out, there is a small possibility that userspace has
opened and mapped the device in the time between cdev_add() and the
device_add() failure. We need a new kill_dax_dev() helper to invalidate
any established mappings.
Fixes: ba09c01d2fa8 ("dax: convert to the cdev api")
Reported-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/dax/dax.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c index 53a016c3dffa..b88b2a2f70f4 100644 --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -646,13 +646,10 @@ static void dax_dev_release(struct device *dev) kfree(dax_dev); } -static void unregister_dax_dev(void *dev) +static void kill_dax_dev(struct dax_dev *dax_dev) { - struct dax_dev *dax_dev = to_dax_dev(dev); struct cdev *cdev = &dax_dev->cdev; - dev_dbg(dev, "%s\n", __func__); - /* * Note, rcu is not protecting the liveness of dax_dev, rcu is * ensuring that any fault handlers that might have seen @@ -664,6 +661,15 @@ static void unregister_dax_dev(void *dev) synchronize_srcu(&dax_srcu); unmap_mapping_range(dax_dev->inode->i_mapping, 0, 0, 1); cdev_del(cdev); +} + +static void unregister_dax_dev(void *dev) +{ + struct dax_dev *dax_dev = to_dax_dev(dev); + + dev_dbg(dev, "%s\n", __func__); + + kill_dax_dev(dax_dev); device_unregister(dev); } @@ -740,6 +746,7 @@ 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) { + kill_dax_dev(dax_dev); put_device(dev); return ERR_PTR(rc); } |