在 2025/8/25 16:20, Zhangfei Gao 写道:
On Fri, 22 Aug 2025 at 18:39, Chenghai Huang <huangchenghai2@xxxxxxxxxx> wrote:
From: Wenkai Lin <linwenkai6@xxxxxxxxxxxxx>
If adding uacce cdev to the system fails, it could be due to two
reasons: either the device's devt exists when the failure occurs,
or the device_add operation fails. In the latter case, cdev_del
will be executed, but in the former case, it will not, leading to a
resource leak. Therefore, it is necessary to perform the cdev_del
action during abnormal exit.
Fixes: 015d239ac014 ("uacce: add uacce driver")
Signed-off-by: Wenkai Lin <linwenkai6@xxxxxxxxxxxxx>
Signed-off-by: Chenghai Huang <huangchenghai2@xxxxxxxxxx>
---
drivers/misc/uacce/uacce.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index 42e7d2a2a90c..3604f722ed60 100644
--- 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 +531,14 @@ int uacce_register(struct uacce_device *uacce)
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) {
+ cdev_del(uacce->cdev);
Can cdev_del be called multi-times? since cdev_device_add may call
cdev_device_add itself.
Does this introduce another issue?
Not understand the case: "either the device's devt exists when the
failure occurs,"
Looks it is cdev_device_add itself issue, or need add check
if (uacce->dev.devt)
cdev_del(uacce->cdev);
how about other drivers' behavior.
When devt is non-zero, there is still no way to distinguish whether cdev_del
has been executed internally, which might be a restriction of
cdev_device_add.
Other drivers often use cdev_init, which does not require consideration
of memory leak, perhaps uacce should use this method too, the plan is to
modify it in v2.
Thanks
