Hello,
Thanks for your patch.
However, as far as I understand, applying it will cause a Use After Free
(UAF) error by cdev_del(), as the call to kobject_put() unwinds the
memory allocation made by cdev_alloc().
Or have I missed something?
Regards,
Eli
On 10/03/2025 4:28, Ma Ke wrote:
After cdev_alloc() succeed and cdev_add() failed, call cdev_del() to
remove unit->cdev from the system properly.
Found by code review.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 8cb5d216ab33 ("char: xillybus: Move class-related functions to new xillybus_class.c")
Signed-off-by: Ma Ke <make24@xxxxxxxxxxx>
---
drivers/char/xillybus/xillybus_class.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/char/xillybus/xillybus_class.c b/drivers/char/xillybus/xillybus_class.c
index c92a628e389e..045e125ec423 100644
--- a/drivers/char/xillybus/xillybus_class.c
+++ b/drivers/char/xillybus/xillybus_class.c
@@ -105,7 +105,7 @@ int xillybus_init_chrdev(struct device *dev,
dev_err(dev, "Failed to add cdev.\n");
/* kobject_put() is normally done by cdev_del() */
kobject_put(&unit->cdev->kobj);
- goto unregister_chrdev;
+ goto err_cdev;
}
for (i = 0; i < num_nodes; i++) {
@@ -157,6 +157,7 @@ int xillybus_init_chrdev(struct device *dev,
device_destroy(&xillybus_class, MKDEV(unit->major,
i + unit->lowest_minor));
+err_cdev:
cdev_del(unit->cdev);
unregister_chrdev:
