[PATCH 13/14] scsi: utilize new device_add_cdev helper function

Logan Gunthorpe
2017-02-21T05:00:52Z

Note: the chardev instance in osd_uld.c originally did not
set the kobject parent. Thus, I'm reasonably confident that because
of this, this code would have suffered from a minor use after free
bug if the cdev was open when the backing device was released.

Signed-off-by: Logan Gunthorpe <logang-OTvnGxWRz7hWk0Htik3J/w@public.gmane.org>
---
drivers/scsi/osd/osd_uld.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/osd/osd_uld.c b/drivers/scsi/osd/osd_uld.c
index 243eab3..519be56 100644
--- a/drivers/scsi/osd/osd_uld.c
+++ b/drivers/scsi/osd/osd_uld.c
@@ -473,18 +473,19 @@ static int osd_probe(struct device *dev)
goto err_put_disk;
}

+ device_initialize(&oud->class_dev);
+ oud->class_dev.devt = MKDEV(SCSI_OSD_MAJOR, oud->minor);
+
/* 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);
+ error = device_add_cdev(&oud->class_dev, &oud->cdev);
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;
@@ -494,7 +495,7 @@ static int osd_probe(struct device *dev)
goto err_put_cdev;
}

- error = device_register(&oud->class_dev);
+ error = device_add(&oud->class_dev);
if (error) {
OSD_ERR("device_register failed => %d\n", error);
goto err_put_cdev;
--
2.1.4