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Date:   Tue, 20 Apr 2021 08:54:29 +0800
From:   Peter Chen <peter.chen@kernel.org>
To:     Wesley Cheng <wcheng@codeaurora.org>
Cc:     balbi@kernel.org, gregkh@linuxfoundation.org,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        jackp@codeaurora.org, Hemant Kumar <hemantk@codeaurora.org>
Subject: Re: [PATCH] usb: gadget: Fix double free of device descriptor
 pointers
Message-ID: <20210420005429.GA5069@nchen>
References: <1618862240-5965-1-git-send-email-wcheng@codeaurora.org>
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On 21-04-19 12:57:20, Wesley Cheng wrote:
> From: Hemant Kumar <hemantk@codeaurora.org>
> 
> Upon driver unbind usb_free_all_descriptors() function frees all
> speed descriptor pointers without setting them to NULL. In case
> gadget speed changes (i.e from super speed plus to super speed)
> after driver unbind only upto super speed descriptor pointers get
> populated. Super speed plus desc still holds the stale (already
> freed) pointer. Fix this issue by setting all descriptor pointers
> to NULL after freeing them in usb_free_all_descriptors().
> 
> Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>
> Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
> ---
>  drivers/usb/gadget/config.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/usb/gadget/config.c b/drivers/usb/gadget/config.c
> index 2d11535..8bb2577 100644
> --- a/drivers/usb/gadget/config.c
> +++ b/drivers/usb/gadget/config.c
> @@ -194,9 +194,13 @@ EXPORT_SYMBOL_GPL(usb_assign_descriptors);
>  void usb_free_all_descriptors(struct usb_function *f)
>  {
>  	usb_free_descriptors(f->fs_descriptors);
> +	f->fs_descriptors = NULL;
>  	usb_free_descriptors(f->hs_descriptors);
> +	f->hs_descriptors = NULL;
>  	usb_free_descriptors(f->ss_descriptors);
> +	f->ss_descriptors = NULL;
>  	usb_free_descriptors(f->ssp_descriptors);
> +	f->ssp_descriptors = NULL;
>  }
>  EXPORT_SYMBOL_GPL(usb_free_all_descriptors);
>  

Reviewed-by: Peter Chen <peter.chen@kernel.org>

You may add Fixed-by tag, and cc to stable tree.

-- 

Thanks,
Peter Chen