linux-kernel - Re: [PATCH 1/4] uacce: fix for cdev memory leak

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CABQgh9GwQ6mB1q12X8pci=QTCw4R7f4CXLkwMfT-VvGeM+qqkw@mail.gmail.com>
Date: Mon, 25 Aug 2025 16:20:35 +0800
From: Zhangfei Gao <zhangfei.gao@...aro.org>
To: Chenghai Huang <huangchenghai2@...wei.com>
Cc: gregkh@...uxfoundation.org, wangzhou1@...ilicon.com, 
	linux-kernel@...r.kernel.org, linuxarm@...wei.com, 
	linux-crypto@...r.kernel.org, fanghao11@...wei.com, shenyang39@...wei.com, 
	qianweili@...wei.com, linwenkai6@...ilicon.com, liulongfang@...wei.com
Subject: Re: [PATCH 1/4] uacce: fix for cdev memory leak

On Fri, 22 Aug 2025 at 18:39, Chenghai Huang <huangchenghai2@...wei.com> wrote:
>
> From: Wenkai Lin <linwenkai6@...ilicon.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@...ilicon.com>
> Signed-off-by: Chenghai Huang <huangchenghai2@...wei.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