netdev - Re: [PATCH net] team: don't call netdev_change

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Wed, 25 May 2016 17:00:40 +0200
From:	Jiri Pirko <jiri@...nulli.us>
To:	Ivan Vecera <ivecera@...hat.com>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH net] team: don't call netdev_change_features under
 team->lock

Wed, May 25, 2016 at 04:55:49PM CEST, ivecera@...hat.com wrote:
>The team_device_event() notifier calls team_compute_features() to fix
>vlan_features under team->lock to protect team->port_list. The problem is
>that subsequent __team_compute_features() calls netdev_change_features()
>to propagate vlan_features to upper vlan devices while team->lock is still
>taken. This can lead to deadlock when NETIF_F_LRO is modified on lower
>devices or team device itself.
>
>Example:
>The team0 as active backup with eth0 and eth1 NICs. Both eth0 & eth1 are
>LRO capable and LRO is enabled. Thus LRO is also enabled on team0.
>
>The command 'ethtool -K team0 lro off' now hangs due to this deadlock:
>
>dev_ethtool()
>-> ethtool_set_features()
> -> __netdev_update_features(team)
>  -> netdev_sync_lower_features()
>   -> netdev_update_features(lower_1)
>    -> __netdev_update_features(lower_1)
>    -> netdev_features_change(lower_1)
>     -> call_netdevice_notifiers(...)
>      -> team_device_event(lower_1)
>       -> team_compute_features(team) [TAKES team->lock]
>        -> netdev_change_features(team)
>         -> __netdev_update_features(team)
>          -> netdev_sync_lower_features()
>           -> netdev_update_features(lower_2)
>            -> __netdev_update_features(lower_2)
>            -> netdev_features_change(lower_2)
>             -> call_netdevice_notifiers(...)
>              -> team_device_event(lower_2)
>               -> team_compute_features(team) [DEADLOCK]
>
>Cc: Jiri Pirko <jiri@...nulli.us>
>
>Signed-off-by: Ivan Vecera <ivecera@...hat.com>

Please add "Fixes:" line.
Thanks!

Signed-off-by: Jiri Pirko <jiri@...lanox.com>