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authorIvan Vecera <ivecera@redhat.com>2016-05-25 22:21:52 +0300
committerDavid S. Miller <davem@davemloft.net>2016-05-25 22:58:04 +0300
commitf6988cb63a4e698d8a62a1d085d263d1fcc351ea (patch)
treeb1be0629b9df70f94c70d376b150b4a6577f130a /drivers/net/team
parentf58fb330121d072fdfd8b36403bc421899fe8a40 (diff)
downloadlinux-f6988cb63a4e698d8a62a1d085d263d1fcc351ea.tar.xz
team: don't call netdev_change_features under team->lock
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>
Diffstat (limited to 'drivers/net/team')
-rw-r--r--drivers/net/team/team.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index a0f64cba86ba..2ace126533cd 100644
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -990,7 +990,7 @@ static void team_port_disable(struct team *team,
#define TEAM_ENC_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG | \
NETIF_F_RXCSUM | NETIF_F_ALL_TSO)
-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;
@@ -1021,15 +1021,20 @@ 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)