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Message-Id: <1489776503-3151-16-git-send-email-logang@deltatee.com>
Date: Fri, 17 Mar 2017 12:48:22 -0600
From: Logan Gunthorpe <logang@...tatee.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Dan Williams <dan.j.williams@...el.com>,
Hans Verkuil <hans.verkuil@...co.com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
Johannes Thumshirn <jthumshirn@...e.de>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Linus Walleij <linus.walleij@...aro.org>,
Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
"James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
David Woodhouse <dwmw2@...radead.org>,
Brian Norris <computersforpeace@...il.com>,
Boris Brezillon <boris.brezillon@...e-electrons.com>,
Marek Vasut <marek.vasut@...il.com>,
Cyrille Pitchen <cyrille.pitchen@...el.com>
Cc: linux-pci@...r.kernel.org, linux-scsi@...r.kernel.org,
rtc-linux@...glegroups.com, linux-mtd@...ts.infradead.org,
linux-media@...r.kernel.org, linux-iio@...r.kernel.org,
linux-rdma@...r.kernel.org, linux-gpio@...r.kernel.org,
linux-input@...r.kernel.org, linux-nvdimm@...ts.01.org,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
Logan Gunthorpe <logang@...tatee.com>
Subject: [PATCH v5 15/16] scsi: utilize new cdev_device_add helper function
This driver did not set kobj.parent so it likely suffered from
a potential use after free race if the user unregistered the
device while it was in use.
This was not so straightforward a conversion but I think this patch
cleans up its probe's error path significantly.
This patch adds device_initialize, which is required for
cdev_device_add. Then it switches to put_device instead of kfree as
recommended by device_initialize's documentation. This removes a lot
from the error path which was already in __remove.
A couple things needed to be re-ordered to be entirely correct, though.
ida_remove is also moved out of __remove and into unregister to
simplify things and follow the pattern other devices are using.
This also drop an extra unnecessary get_device/put_device in the code.
Signed-off-by: Logan Gunthorpe <logang@...tatee.com>
---
drivers/scsi/osd/osd_uld.c | 56 +++++++++++++++++-----------------------------
1 file changed, 20 insertions(+), 36 deletions(-)
diff --git a/drivers/scsi/osd/osd_uld.c b/drivers/scsi/osd/osd_uld.c
index e0ce5d2..4101c31 100644
--- a/drivers/scsi/osd/osd_uld.c
+++ b/drivers/scsi/osd/osd_uld.c
@@ -400,9 +400,6 @@ static void __remove(struct device *dev)
kfree(oud->odi.osdname);
- if (oud->cdev.owner)
- cdev_del(&oud->cdev);
-
osd_dev_fini(&oud->od);
scsi_device_put(scsi_device);
@@ -411,7 +408,6 @@ static void __remove(struct device *dev)
if (oud->disk)
put_disk(oud->disk);
- ida_remove(&osd_minor_ida, oud->minor);
kfree(oud);
}
@@ -446,8 +442,20 @@ static int osd_probe(struct device *dev)
if (NULL == oud)
goto err_retract_minor;
+ /* class device member */
+ device_initialize(&oud->class_dev);
dev_set_drvdata(dev, oud);
oud->minor = minor;
+ oud->class_dev.devt = MKDEV(SCSI_OSD_MAJOR, oud->minor);
+ oud->class_dev.class = &osd_uld_class;
+ oud->class_dev.parent = dev;
+ oud->class_dev.release = __remove;
+
+ /* hold one more reference to the scsi_device that will get released
+ * in __release, in case a logout is happening while fs is mounted
+ */
+ scsi_device_get(scsi_device);
+ osd_dev_init(&oud->od, scsi_device);
/* allocate a disk and set it up */
/* FIXME: do we need this since sg has already done that */
@@ -461,59 +469,34 @@ static int osd_probe(struct device *dev)
sprintf(disk->disk_name, "osd%d", oud->minor);
oud->disk = disk;
- /* hold one more reference to the scsi_device that will get released
- * in __release, in case a logout is happening while fs is mounted
- */
- scsi_device_get(scsi_device);
- osd_dev_init(&oud->od, scsi_device);
-
/* Detect the OSD Version */
error = __detect_osd(oud);
if (error) {
OSD_ERR("osd detection failed, non-compatible OSD device\n");
- goto err_put_disk;
+ goto err_free_osd;
}
/* init the char-device for communication with user-mode */
cdev_init(&oud->cdev, &osd_fops);
oud->cdev.owner = THIS_MODULE;
- error = cdev_add(&oud->cdev,
- MKDEV(SCSI_OSD_MAJOR, oud->minor), 1);
- if (error) {
- OSD_ERR("cdev_add failed\n");
- goto err_put_disk;
- }
- /* class device member */
- oud->class_dev.devt = oud->cdev.dev;
- oud->class_dev.class = &osd_uld_class;
- oud->class_dev.parent = dev;
- oud->class_dev.release = __remove;
error = dev_set_name(&oud->class_dev, "%s", disk->disk_name);
if (error) {
OSD_ERR("dev_set_name failed => %d\n", error);
- goto err_put_cdev;
+ goto err_free_osd;
}
- error = device_register(&oud->class_dev);
+ error = cdev_device_add(&oud->cdev, &oud->class_dev);
if (error) {
OSD_ERR("device_register failed => %d\n", error);
- goto err_put_cdev;
+ goto err_free_osd;
}
- get_device(&oud->class_dev);
-
OSD_INFO("osd_probe %s\n", disk->disk_name);
return 0;
-err_put_cdev:
- cdev_del(&oud->cdev);
-err_put_disk:
- scsi_device_put(scsi_device);
- put_disk(disk);
err_free_osd:
- dev_set_drvdata(dev, NULL);
- kfree(oud);
+ put_device(&oud->class_dev);
err_retract_minor:
ida_remove(&osd_minor_ida, minor);
return error;
@@ -530,9 +513,10 @@ static int osd_remove(struct device *dev)
scsi_device);
}
- device_unregister(&oud->class_dev);
-
+ cdev_device_del(&oud->cdev, &oud->class_dev);
+ ida_remove(&osd_minor_ida, oud->minor);
put_device(&oud->class_dev);
+
return 0;
}
--
2.1.4
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