[PATCH 6.18 191/227] uacce: fix cdev handling in the cleanup path

Greg Kroah-Hartman
2026-01-28T16:00:49Z

From: Wenkai Lin <linwenkai6@hisilicon.com>

commit a3bece3678f6c88db1f44c602b2a63e84b4040ac upstream.

When cdev_device_add fails, it internally releases the cdev memory,
and if cdev_device_del is then executed, it will cause a hang error.
To fix it, we check the return value of cdev_device_add() and clear
uacce->cdev to avoid calling cdev_device_del in the uacce_remove.

Fixes: 015d239ac014 ("uacce: add uacce driver")
Cc: stable@vger.kernel.org
Signed-off-by: Wenkai Lin <linwenkai6@hisilicon.com>
Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
Acked-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Link: https://patch.msgid.link/20251202061256.4158641-2-huangchenghai2@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/misc/uacce/uacce.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -519,6 +519,8 @@ EXPORT_SYMBOL_GPL(uacce_alloc);
*/
int uacce_register(struct uacce_device *uacce)
{
+ int ret;
+
if (!uacce)
return -ENODEV;

@@ -529,7 +531,11 @@ int uacce_register(struct uacce_device *
uacce->cdev->ops = &uacce_fops;
uacce->cdev->owner = THIS_MODULE;

- return cdev_device_add(uacce->cdev, &uacce->dev);
+ ret = cdev_device_add(uacce->cdev, &uacce->dev);
+ if (ret)
+ uacce->cdev = NULL;
+
+ return ret;
}
EXPORT_SYMBOL_GPL(uacce_register);