Re: [Internet]Re: [PATCH net-next v4 4/4] net: tun: track dropped skb via kfree_skb_reason()

[imagedong(董梦龙)]

On 2022/3/2 AM 11:29，“David Ahern”<dsahern@xxxxxxxxx> write:

>On 3/1/22 7:50 PM, Jakub Kicinski wrote:
>> On Sat, 26 Feb 2022 00:49:29 -0800 Dongli Zhang wrote:
>>> +	SKB_DROP_REASON_SKB_PULL,	/* failed to pull sk_buff data */
>>> +	SKB_DROP_REASON_SKB_TRIM,	/* failed to trim sk_buff data */
>> 
[...]
>>>  	SKB_DROP_REASON_DEV_HDR,	/* there is something wrong with
>>>  					 * device driver specific header
>>>  					 */
>>> +	SKB_DROP_REASON_DEV_READY,	/* device is not ready */
>> 
>> What is ready? link is not up? peer not connected? can we expand?
>
>As I recall in this case it is the tfile for a tun device disappeared -
>ie., a race condition.

This seems is that tun is not attached to a file (the tun device file
is not opened?) Maybe TAP_UNATTACHED is more suitable :)