Very clear explanation，thank you! :-) Zhangjie
-----Original Message----- From: Eric Dumazet [mailto:eric.duma...@gmail.com] Sent: Wednesday, August 26, 2015 9:10 PM To: Zhangjie (HZ) Cc: Jason Wang; netdev@vger.kernel.org; Qinchuanyu; Yewudi; liuyongan 00175866; Wangbicheng; Yan Chen Subject: Re: [Question] Usage of dev_hold()/dev_put() On Wed, 2015-08-26 at 07:48 +0000, Zhangjie (HZ) wrote: > Eric, > Thank you for your patient apply. > There is still a question, > In receive path, driver does not call dev_hold(), when skb goes to host > stack, skb->dev is likely to be used. > If device is destroyed before that, it seems dangerous. This is also handled properly. Check : flush_backlog() in net/core/dev.c sock_queue_rcv_skb() , and all functions setting skb->dev to NULL
