From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ale.deltatee.com ([207.54.116.67]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1chsVf-0000kj-Ol for linux-mtd@lists.infradead.org; Sun, 26 Feb 2017 06:40:45 +0000 From: Logan Gunthorpe To: Greg Kroah-Hartman , Dan Williams , Alexander Viro , Johannes Thumshirn , Jan Kara , Arnd Bergmann , Sajjan Vikas C , Dmitry Torokhov , Linus Walleij , Alexandre Courbot , Peter Huewe , Marcel Selhorst , Jarkko Sakkinen , Jason Gunthorpe , Olof Johansson , Doug Ledford , Sean Hefty , Hal Rosenstock , Dmitry Vyukov , Haggai Eran , Parav Pandit , Leon Romanovsky , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Hans Verkuil , Mauro Carvalho Chehab , Artem Bityutskiy , Richard Weinberger , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Cyrille Pitchen , Matt Porter , Alexandre Bounine , Andrew Morton , Joe Perches , Lorenzo Stoakes , Vladimir Zapolskiy , Alessandro Zummo , Alexandre Belloni , Boaz Harrosh , "James E.J. Bottomley" , "Martin K. Petersen" , Stephen Bates , Bjorn Helgaas Cc: linux-pci@vger.kernel.org, linux-scsi@vger.kernel.org, rtc-linux@googlegroups.com, linux-mtd@lists.infradead.org, linux-media@vger.kernel.org, linux-iio@vger.kernel.org, linux-rdma@vger.kernel.org, linux-gpio@vger.kernel.org, linux-input@vger.kernel.org, linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, , Logan Gunthorpe Date: Sat, 25 Feb 2017 23:38:03 -0700 Message-Id: <1488091097-12328-3-git-send-email-logang@deltatee.com> In-Reply-To: <1488091097-12328-1-git-send-email-logang@deltatee.com> References: <1488091097-12328-1-git-send-email-logang@deltatee.com> Subject: [PATCH v2 02/16] device-dax: fix cdev leak List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Dan Williams 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") Cc: Cc: Logan Gunthorpe Reported-by: Jason Gunthorpe Signed-off-by: Dan Williams --- drivers/dax/dax.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c index ed758b7..b62a52f 100644 --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -630,13 +630,10 @@ 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 @@ -648,6 +645,15 @@ static void unregister_dax_dev(void *dev) synchronize_rcu(); 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); } @@ -724,6 +730,7 @@ 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); } -- 2.1.4