Re: [PATCH] drivers: net: remove a dangling pointer in peak_usb_create_dev

[Pavel Skripkin <paskripkin@gmail.com>]

Hi Dongliang,

On 1/20/22 16:05, Dongliang Mu wrote:
> From: Dongliang Mu <mudongliangabcd@gmail.com>
> 
> The error handling code of peak_usb_create_dev forgets to reset the
> next_siblings of previous entry.
> 
> Fix this by nullifying the (dev->prev_siblings)->next_siblings in the
> error handling code.
> 
> Signed-off-by: Dongliang Mu <mudongliangabcd@gmail.com>
> ---
>   drivers/net/can/usb/peak_usb/pcan_usb_core.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
> index b850ff8fe4bd..f858810221b6 100644
> --- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
> +++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
> @@ -894,6 +894,9 @@ static int peak_usb_create_dev(const struct peak_usb_adapter *peak_usb_adapter,
>   		dev->adapter->dev_free(dev);
>   
>   lbl_unregister_candev:
> +	/* remove the dangling pointer in next_siblings */
> +	if (dev->prev_siblings)
> +		(dev->prev_siblings)->next_siblings = NULL;
>   	unregister_candev(netdev);
>   
>   lbl_restore_intf_data:


Is this pointer used somewhere? I see, that couple of
struct peak_usb_adapter::dev_free() functions use it, but
peak_usb_disconnect() sets dev->next_siblings to NULL before calling 
->dev_free().

Do you have a calltrace or oops log?




With regards,
Pavel Skripkin