Re: 回复: 回复: [PATCH v2] usb: gadget: function: printer: fix use-after-free in __lock_acquire

[Greg KH]

On Wed, Jun 10, 2020 at 04:58:44AM +, Zhang, Qiang wrote:
> cdev  object reference count and "struct printer_dev" object
> reference count(kref), This two reference counts do not conflict.  in
> file usb-skeleton.c also used a similar method， "struct usb_skel"
> contains kref members.

I do not understand what you are referring to here, sorry.

greg k-h

回复: 回复: [PATCH v2] usb: gadget: function: printer: fix use-after-free in __lock_acquire

[Zhang, Qiang]

cdev  object reference count and "struct printer_dev" object  reference 
count(kref), This two reference counts do not conflict.  in file usb-skeleton.c 
also used a similar method， "struct usb_skel"  contains kref members.

thanks,
Zqiang


发件人: Greg KH 
发送时间: 2020年6月9日 17:48
收件人: Zhang, Qiang
抄送: ba...@kernel.org; linux-...@vger.kernel.org; linux-kernel@vger.kernel.org
主题: Re: 回复: [PATCH v2] usb: gadget: function: printer: fix use-after-free in 
__lock_acquire


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A: No.
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http://daringfireball.net/2007/07/on_top

On Tue, Jun 09, 2020 at 09:35:11AM +, Zhang, Qiang wrote:
> Thank you for your suggestion
> two referenced counted objects in the same exact structure. another  
> referenced is
> "dev->printer_cdev_open"?

Maybe, I don't know, but a cdev does have a reference count already,
right?  Why do you need printer_cdev_open as well?

thanks,

greg k-h