On 1/8/19 12:14 PM, Eric Dumazet wrote: > On Tue, Jan 8, 2019 at 3:08 AM Piotr Sawicki > <p.sawic...@partner.samsung.com> wrote: > >> Yes I know. It looks like the Smack's security rule was changed during this >> process. >> >> Firstly the packet was allowed to be received and it was put into the >> backlog queue. Then, the >> >> rule was changed, and during the release phase LSM was called again for the >> same packet. >> >> But this time, Smack denied access and tried to send an ICMPv6 packet to >> inform a peer. >> >> I want to make sure if it is the root cause of this problem. >> >> >> Besides, what is the purpose of setting skb->dev to NULL in >> __sk_receive_skb() ? > > We can not keep a pointer to the device, the device might be > dismantled/freed before socket backlog can be processed. > > Input processing is using RCU, meaning no refcount is taken on the device.
Thanks for explanation.
