diff options
| author | Ivan Vecera <ivecera@redhat.com> | 2016-05-25 21:21:52 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-06-24 10:18:17 -0700 |
| commit | 13a055d6ca34dcce324ccfab63cc05db726030bc (patch) | |
| tree | 8790ab977458e62e53681e9db9f93cd7c57a0eaf /drivers/net/team | |
| parent | 450db517b9223908ab5c1a9b5ddce3b6c4d75b18 (diff) | |
team: don't call netdev_change_features under team->lock
[ Upstream commit f6988cb63a4e698d8a62a1d085d263d1fcc351ea ]
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]
The bug is present in team from the beginning but it appeared after the commit
fd867d5 (net/core: generic support for disabling netdev features down stack)
that adds synchronization of features with lower devices.
Fixes: fd867d5 (net/core: generic support for disabling netdev features down stack)
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net/team')
| -rw-r--r-- | drivers/net/team/team.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c index 59fefca74263..a5f392ae30d5 100644 --- a/drivers/net/team/team.c +++ b/drivers/net/team/team.c @@ -969,7 +969,7 @@ static void team_port_disable(struct team *team, NETIF_F_FRAGLIST | NETIF_F_ALL_TSO | \ NETIF_F_HIGHDMA | NETIF_F_LRO) -static void __team_compute_features(struct team *team) +static void ___team_compute_features(struct team *team) { struct team_port *port; u32 vlan_features = TEAM_VLAN_FEATURES & NETIF_F_ALL_FOR_ALL; @@ -993,15 +993,20 @@ static void __team_compute_features(struct team *team) team->dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; if (dst_release_flag == (IFF_XMIT_DST_RELEASE | IFF_XMIT_DST_RELEASE_PERM)) team->dev->priv_flags |= IFF_XMIT_DST_RELEASE; +} +static void __team_compute_features(struct team *team) +{ + ___team_compute_features(team); netdev_change_features(team->dev); } static void team_compute_features(struct team *team) { mutex_lock(&team->lock); - __team_compute_features(team); + ___team_compute_features(team); mutex_unlock(&team->lock); + netdev_change_features(team->dev); } static int team_port_enter(struct team *team, struct team_port *port) |