[v1] usb: gadget: f_hid: drop ERROR() on copy_from_user() failure

[PATCH] usb: gadget: f_hid: drop ERROR() on copy_from_user() failure

Posted by Linkai Gong 1 month, 1 week ago

A failed copy_from_user() is a userspace error and should not spam the
kernel log. Just free the temporary entry and return.

Suggested-by: David Laight <david.laight.linux@gmail.com>
Signed-off-by: Linkai Gong <gonglinkai@kylinos.cn>
---
 drivers/usb/gadget/function/f_hid.c | 1 -
 1 file changed, 1 deletion(-)
diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index 3c6b43d06a6d..5c39da1ac7a6 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -656,7 +656,6 @@ static int f_hidg_get_report(struct file *file, struct usb_hidg_report __user *b
 
 	if (copy_from_user(&entry->report_data, buffer,
 				sizeof(struct usb_hidg_report))) {
-		ERROR(cdev, "copy_from_user error\n");
 		kfree(entry);
 		return -EINVAL;
 	}
-- 
2.25.1

Re: [PATCH] usb: gadget: f_hid: drop ERROR() on copy_from_user() failure

Posted by David Laight 1 month, 1 week ago

On Tue, 18 Aug 2026 09:21:18 +0800
Linkai Gong <gonglinkai@kylinos.cn> wrote:

> A failed copy_from_user() is a userspace error and should not spam the
> kernel log. Just free the temporary entry and return.
> 
> Suggested-by: David Laight <david.laight.linux@gmail.com>
> Signed-off-by: Linkai Gong <gonglinkai@kylinos.cn>
> ---
>  drivers/usb/gadget/function/f_hid.c | 1 -
>  1 file changed, 1 deletion(-)
> diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
> index 3c6b43d06a6d..5c39da1ac7a6 100644
> --- a/drivers/usb/gadget/function/f_hid.c
> +++ b/drivers/usb/gadget/function/f_hid.c
> @@ -656,7 +656,6 @@ static int f_hidg_get_report(struct file *file, struct usb_hidg_report __user *b
>  
>  	if (copy_from_user(&entry->report_data, buffer,
>  				sizeof(struct usb_hidg_report))) {
> -		ERROR(cdev, "copy_from_user error\n");
>  		kfree(entry);
>  		return -EINVAL;

This should be -EFAULT.

David

>  	}

Re: [PATCH] usb: gadget: f_hid: drop ERROR() on copy_from_user() failure

Posted by Peter Korsgaard 1 month, 1 week ago

>>>>> "Linkai" == Linkai Gong <gonglinkai@kylinos.cn> writes:

 > A failed copy_from_user() is a userspace error and should not spam the
 > kernel log. Just free the temporary entry and return.

 > Suggested-by: David Laight <david.laight.linux@gmail.com>
 > Signed-off-by: Linkai Gong <gonglinkai@kylinos.cn>

Acked-by: Peter Korsgaard <peter@korsgaard.com>

> ---
 >  drivers/usb/gadget/function/f_hid.c | 1 -
 >  1 file changed, 1 deletion(-)

 > diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
 > index 3c6b43d06a6d..5c39da1ac7a6 100644
 > --- a/drivers/usb/gadget/function/f_hid.c
 > +++ b/drivers/usb/gadget/function/f_hid.c
 > @@ -656,7 +656,6 @@ static int f_hidg_get_report(struct file *file, struct usb_hidg_report __user *b
 
 >  	if (copy_from_user(&entry->report_data, buffer,
 >  				sizeof(struct usb_hidg_report))) {
 > -		ERROR(cdev, "copy_from_user error\n");
 >  		kfree(entry);
 >  		return -EINVAL;
 >  	}
 > -- 

 > 2.25.1


-- 
Bye, Peter Korsgaard

[PATCH v2] usb: gadget: f_hid: drop ERROR() on copy_from_user() failure

Posted by Linkai Gong 1 month, 1 week ago

A failed copy_from_user() is a userspace fault, not a kernel error.
Do not spam the log, and return -EFAULT instead of -EINVAL.

Suggested-by: David Laight <david.laight.linux@gmail.com>
Signed-off-by: Linkai Gong <gonglinkai@kylinos.cn>
---
v2:
- Return -EFAULT instead of -EINVAL (David Laight)

 drivers/usb/gadget/function/f_hid.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_hid.c b/drivers/usb/gadget/function/f_hid.c
index 3c6b43d06a6d..b8e1c0e0f1a2 100644
--- a/drivers/usb/gadget/function/f_hid.c
+++ b/drivers/usb/gadget/function/f_hid.c
@@ -656,9 +656,8 @@ static int f_hidg_get_report(struct file *file, struct usb_hidg_report __user *b
 
 	if (copy_from_user(&entry->report_data, buffer,
 				sizeof(struct usb_hidg_report))) {
-		ERROR(cdev, "copy_from_user error\n");
 		kfree(entry);
-		return -EINVAL;
+		return -EFAULT;
 	}
 
 	report_id = entry->report_data.report_id;
-- 
2.25.1