From: Wenkai Lin <linwenkai6@hisilicon.com>
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@hisilicon.com>
Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
---
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);
+ uacce->cdev = NULL;
+ return ret;
+ }
+
+ return 0;
}
EXPORT_SYMBOL_GPL(uacce_register);
--
2.33.0On Fri, 22 Aug 2025 at 18:39, Chenghai Huang <huangchenghai2@huawei.com> wrote:
>
> From: Wenkai Lin <linwenkai6@hisilicon.com>
>
> 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@hisilicon.com>
> Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
> ---
> 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.
Thanks
在 2025/8/25 16:20, Zhangfei Gao 写道:
> On Fri, 22 Aug 2025 at 18:39, Chenghai Huang <huangchenghai2@huawei.com> wrote:
>> From: Wenkai Lin <linwenkai6@hisilicon.com>
>>
>> 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@hisilicon.com>
>> Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
>> ---
>> 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
On Fri, Aug 22, 2025 at 06:39:01PM +0800, Chenghai Huang wrote:
> From: Wenkai Lin <linwenkai6@hisilicon.com>
>
> 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@hisilicon.com>
> Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
> ---
> 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);
> + uacce->cdev = NULL;
> + return ret;
> + }
> +
> + return 0;
> }
> EXPORT_SYMBOL_GPL(uacce_register);
>
> --
> 2.33.0
>
Hi,
This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
a patch that has triggered this response. He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created. Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.
You are receiving this message because of the following common error(s)
as indicated below:
- You have marked a patch with a "Fixes:" tag for a commit that is in an
older released kernel, yet you do not have a cc: stable line in the
signed-off-by area at all, which means that the patch will not be
applied to any older kernel releases. To properly fix this, please
follow the documented rules in the
Documentation/process/stable-kernel-rules.rst file for how to resolve
this.
If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.
thanks,
greg k-h's patch email bot
On Thu, Aug 22, 2025 at 07:27 PM +0800, Greg KH wrote:
> On Fri, Aug 22, 2025 at 06:39:01PM +0800, Chenghai Huang wrote:
>> From: Wenkai Lin <linwenkai6@hisilicon.com>
>>
>> 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@hisilicon.com>
>> Signed-off-by: Chenghai Huang <huangchenghai2@huawei.com>
>> ---
>> 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);
>> + uacce->cdev = NULL;
>> + return ret;
>> + }
>> +
>> + return 0;
>> }
>> EXPORT_SYMBOL_GPL(uacce_register);
>>
>> --
>> 2.33.0
>>
> Hi,
>
> This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
> a patch that has triggered this response. He used to manually respond
> to these common problems, but in order to save his sanity (he kept
> writing the same thing over and over, yet to different people), I was
> created. Hopefully you will not take offence and will fix the problem
> in your patch and resubmit it so that it can be accepted into the Linux
> kernel tree.
>
> You are receiving this message because of the following common error(s)
> as indicated below:
>
> - You have marked a patch with a "Fixes:" tag for a commit that is in an
> older released kernel, yet you do not have a cc: stable line in the
> signed-off-by area at all, which means that the patch will not be
> applied to any older kernel releases. To properly fix this, please
> follow the documented rules in the
> Documentation/process/stable-kernel-rules.rst file for how to resolve
> this.
>
> If you wish to discuss this problem further, or you have questions about
> how to resolve this issue, please feel free to respond to this email and
> Greg will reply once he has dug out from the pending patches received
> from other developers.
>
> thanks,
>
> greg k-h's patch email bot
Okay，I will add it in v2.
Thanks,
ChengHai
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