From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Logan Gunthorpe To: Greg Kroah-Hartman , Dan Williams , Hans Verkuil , Alexander Viro , Alexandre Belloni , Jason Gunthorpe , Johannes Thumshirn , Dmitry Torokhov , Linus Walleij , Jarkko Sakkinen , "James E.J. Bottomley" , "Martin K. Petersen" , David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Cyrille Pitchen 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: Fri, 17 Mar 2017 12:48:15 -0600 Message-Id: <1489776503-3151-9-git-send-email-logang@deltatee.com> In-Reply-To: <1489776503-3151-1-git-send-email-logang@deltatee.com> References: <1489776503-3151-1-git-send-email-logang@deltatee.com> Subject: [PATCH v5 08/16] IB/ucm: utilize new cdev_device_add helper function Sender: linux-kernel-owner@vger.kernel.org List-ID: From: Jason Gunthorpe The use after free is not triggerable here because the cdev holds the module lock and the only device_unregister is only triggered by module unload, however make the change for consistency. To make this work the cdev_del needs to move out of the struct device release function. This cleans up the error path significantly and thus also fixes a minor bug where the devnum would not be released if cdev_add failed. Signed-off-by: Jason Gunthorpe Signed-off-by: Logan Gunthorpe Reviewed-by: Logan Gunthorpe Reviewed-by: Leon Romanovsky --- drivers/infiniband/core/ucm.c | 35 ++++++++++++++++++----------------- 1 file changed, 18 insertions(+), 17 deletions(-) diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c index cc0d51f..d15efa4 100644 --- a/drivers/infiniband/core/ucm.c +++ b/drivers/infiniband/core/ucm.c @@ -1205,12 +1205,15 @@ static void ib_ucm_release_dev(struct device *dev) struct ib_ucm_device *ucm_dev; ucm_dev = container_of(dev, struct ib_ucm_device, dev); - cdev_del(&ucm_dev->cdev); + kfree(ucm_dev); +} + +static void ib_ucm_free_dev(struct ib_ucm_device *ucm_dev) +{ if (ucm_dev->devnum < IB_UCM_MAX_DEVICES) clear_bit(ucm_dev->devnum, dev_map); else clear_bit(ucm_dev->devnum - IB_UCM_MAX_DEVICES, overflow_map); - kfree(ucm_dev); } static const struct file_operations ucm_fops = { @@ -1266,7 +1269,9 @@ static void ib_ucm_add_one(struct ib_device *device) if (!ucm_dev) return; + device_initialize(&ucm_dev->dev); ucm_dev->ib_dev = device; + ucm_dev->dev.release = ib_ucm_release_dev; devnum = find_first_zero_bit(dev_map, IB_UCM_MAX_DEVICES); if (devnum >= IB_UCM_MAX_DEVICES) { @@ -1286,16 +1291,14 @@ static void ib_ucm_add_one(struct ib_device *device) cdev_init(&ucm_dev->cdev, &ucm_fops); ucm_dev->cdev.owner = THIS_MODULE; kobject_set_name(&ucm_dev->cdev.kobj, "ucm%d", ucm_dev->devnum); - if (cdev_add(&ucm_dev->cdev, base, 1)) - goto err; ucm_dev->dev.class = &cm_class; ucm_dev->dev.parent = device->dev.parent; - ucm_dev->dev.devt = ucm_dev->cdev.dev; - ucm_dev->dev.release = ib_ucm_release_dev; + ucm_dev->dev.devt = base; + dev_set_name(&ucm_dev->dev, "ucm%d", ucm_dev->devnum); - if (device_register(&ucm_dev->dev)) - goto err_cdev; + if (cdev_device_add(&ucm_dev->cdev, &ucm_dev->dev)) + goto err_devnum; if (device_create_file(&ucm_dev->dev, &dev_attr_ibdev)) goto err_dev; @@ -1304,15 +1307,11 @@ static void ib_ucm_add_one(struct ib_device *device) return; err_dev: - device_unregister(&ucm_dev->dev); -err_cdev: - cdev_del(&ucm_dev->cdev); - if (ucm_dev->devnum < IB_UCM_MAX_DEVICES) - clear_bit(devnum, dev_map); - else - clear_bit(devnum, overflow_map); + cdev_device_del(&ucm_dev->cdev, &ucm_dev->dev); +err_devnum: + ib_ucm_free_dev(ucm_dev); err: - kfree(ucm_dev); + put_device(&ucm_dev->dev); return; } @@ -1323,7 +1322,9 @@ static void ib_ucm_remove_one(struct ib_device *device, void *client_data) if (!ucm_dev) return; - device_unregister(&ucm_dev->dev); + cdev_device_del(&ucm_dev->cdev, &ucm_dev->dev); + ib_ucm_free_dev(ucm_dev); + put_device(&ucm_dev->dev); } static CLASS_ATTR_STRING(abi_version, S_IRUGO, -- 2.1.4