lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 20 Jan 2012 07:08:50 +0100 From: Hans Schillstrom <hans.schillstrom@...csson.com> To: Hagen Paul Pfeifer <hagen@...u.net> CC: "Eric W. Biederman" <ebiederm@...ssion.com>, David Miller <davem@...emloft.net>, "equinox@...c24.net" <equinox@...c24.net>, "netdev@...r.kernel.org" <netdev@...r.kernel.org> Subject: Re: RFC Hanging clean-up of a namespace On Thursday 19 January 2012 22:40:53 Hagen Paul Pfeifer wrote: > * Eric W. Biederman | 2012-01-19 13:24:13 [-0800]: > > >This thread is a fascinating disconnect from reality all of the way > >around. > > > >- inet_twsk_purge already implements throwing out of timewait sockets > > when a network namespaces is being cleaned up. So the RFC is nonsense. > > This is how it is implemented, not how it should be. TIME_WAIT is not the > problem, it is there to keep the stack from sending wrong RST messages. Maybe > the 2*MSL could be fixed by a more accurate 2*RTT. > I was only refering to my printk's i.e. the last sockets leaving the namespace was from tcp_timer() with state 7, 2 minutes after free_nsproxy() was called. (and assumed that was the time_wait) > >- Keeping the timewait sockets at that point we purge them in the code > > can achieve nothing. We don't have any userspace processes or network > > devices associated with the timewait sockets at the point we get rid > > of them. The network namespace exists so long as a userspace process > > can find it. The network namespace exit is asynchronous in it's own > > workqueue so userspace definitely is not blocked. > One example of a real life problem is when a container crash where a VLAN from a physical interface is used in the container, and you automatically reboot that container. A new namespace is created with that VLAN again and what happens ? That VLAN id is busy (waiting for tcp_timer) and the continer start fails ... So you have to wait a couple of minutes :-( > Another possible solution could be a netns global TIME_WAIT list. But this > is a little bit expensive and out of question - but this _is_ a convenient > solution. > > The "5 second reboot" is no argument - it show a discrepance between TCP > requirements and the actual situation. > -- Regards Hans Schillstrom <hans.schillstrom@...csson.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists