On Tue, Jan 31, 2017 at 9:57 AM, David Laight <david.lai...@aculab.com> wrote: > From: Cong Wang >> Sent: 31 January 2017 17:38 >> On Tue, Jan 31, 2017 at 7:41 AM, David Laight <david.lai...@aculab.com> >> wrote: >> > Commit 26abe1437 changed sock_create_kern() so that it stopped >> > holding a reference to the network namespace. >> > The rational seemed to be 'to allow to stop it' (presumably 'be deleted'). >> > Prior to this change some kernel paths used sk_change_net() (etc) to >> > change the namespace after the socket was created. >> > >> > If the socket doesn't hold a reference to the namespace, what actually >> > happens when the namespace is deleted? >> >> Kernel socket should have the same lifetime with the net namespace, >> that is, created in net_init and released in net_exit. Think about it, if it >> really held a refcnt to this netns, how could this netns be teared down? > > That rather depends on what they are being used for. > Consider something like an in kernel ftp client, it doesn't really care > about namespaces except in as much as the connections it creates must > be inside the correct namespace. > The namespace shouldn't be torn down while that connection exists any more > than it should be torn down while a user process has an open connection. > (Listening sockets are likely to be more of a problem.)
If you don't care about netns, why not just use init_net which is never torn down and make your kernel socket global so that each netns can access it too?
