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: Tue, 06 Aug 2013 11:07:30 +0200 From: Nikolay Aleksandrov <nikolay@...hat.com> To: Veaceslav Falico <vfalico@...hat.com> CC: netdev@...r.kernel.org, fubar@...ibm.com, andy@...yhouse.net, davem@...emloft.net, kaber@...sh.net Subject: Re: [net-next,1/3] bonding: fix vlan 0 addition and removal On 08/06/2013 10:59 AM, Veaceslav Falico wrote: > On Tue, Aug 06, 2013 at 10:39:22AM +0200, Nikolay Aleksandrov wrote: >>> From 1c89abefebe90568ed52d2df59fcfdd650bc4696 Mon Sep 17 00:00:00 2001 >>> From: Veaceslav Falico <vfalico@...hat.com> >>> Date: Mon, 5 Aug 2013 23:29:12 +0200 >>> Subject: [PATCH] bonding: add vlan_uses_dev_rcu() and make bond_vlan_used() >>> use it >>> >>> Currently, bond_vlan_used() looks for any vlan, including the pseudo-vlan >>> id 0, and always returns true if 8021q is loaded. This creates several bad >>> situations - some warnings in __bond_release_one() because it thinks that >>> we still have vlans while removing, sending LB packets with vlan id 0 and, >>> possibly, other caused by vlan id 0. >>> >>> Fix it by adding a new call, vlan_uses_dev_rcu(), which is the same as >>> vlan_uses_dev(), but uses rcu_dereference() instead of rtnl, and thus we >>> can use it in bond_vlan_used() wrapped in rcu_read_lock(). >>> >>> Also, use the pure vlan_uses_dev() in __bond_release_one() cause the rtnl >>> lock is held there. >>> >> Just 1 more note, you can't trust nr_vlan_devs under RCU. > > Yes, you're right, however we actually don't care anyway if we race with > (un)register_vlan_dev() - we'll end up either in using the (un)registered > vlan or not, and in both cases it's ok. So I don't see a real problem here, > tbh, though I'll look into this also. You might have stale value in the cache, the implications don't stop there. I'd like to avoid inconsistent behaviour if there's a way. A solution that can be relied on and works always would be much more preferable. -- 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