Nikolay Aleksandrov
2019-Aug-02 00:38 UTC
[Bridge] [PATCH net v3] net: bridge: move vlan init/deinit to NETDEV_REGISTER/UNREGISTER
On 8/1/19 1:49 AM, Nikolay Aleksandrov wrote: [snip]> [0] https://bugzilla.kernel.org/show_bug.cgi?id=204389 > > Reported-by: michael-dev <michael-dev at fami-braun.de> > Fixes: 5be5a2df40f0 ("bridge: Add filtering support for default_pvid") > Signed-off-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com> > --- > I tried a few different approaches to resolve this but they were all > unsuitable for some kernels, this approach can go to stables easily > and IMO is the way this had to be done from the start. Alternatively > we could move only the br_vlan_add and pair it with a br_vlan_del of > default_pvid on the same events, but I don't think it hurts to move > the whole init/deinit there as it'd help older stable releases as well. > > I also tested the br_vlan_init error handling after the move by always > returning errors from all over it. Since errors at NETDEV_REGISTER cause > NETDEV_UNREGISTER we can deinit vlans properly for all cases regardless > why it happened (e.g. device destruction or init error). > > net/bridge/br.c | 5 ++++- > net/bridge/br_device.c | 10 ---------- > net/bridge/br_private.h | 20 +++++--------------- > net/bridge/br_vlan.c | 25 ++++++++++++++++++------- > 4 files changed, 27 insertions(+), 33 deletions(-) >Self-NAK, after thinking more about how to best handle this and running more tests I believe it'll be better to go with the alternative I suggested above - to move out only the default pvid add out of br_vlan_init to NETDEV_REGSITER and pair it with br_vlan_delete in NETDEV_UNREGISTER. That way we'll split the init/deinit in 2 steps, but we'll keep the current order and will reduce the churn for this fix, functionally it should be equivalent as that is the problematic part of the init which has to be done after the netdev has been registered. I'll spin v4 tomorrow after running more tests with it.
Nikolay Aleksandrov
2019-Aug-02 10:57 UTC
[Bridge] [PATCH net v4] net: bridge: move default pvid init/deinit to NETDEV_REGISTER/UNREGISTER
Most of the bridge device's vlan init bugs come from the fact that its default pvid is created at the wrong time, way too early in ndo_init() before the device is even assigned an ifindex. It introduces a bug when the bridge's dev_addr is added as fdb during the initial default pvid creation the notification has ifindex/NDA_MASTER both equal to 0 (see example below) which really makes no sense for user-space[0] and is wrong. Usually user-space software would ignore such entries, but they are actually valid and will eventually have all necessary attributes. It makes much more sense to send a notification *after* the device has registered and has a proper ifindex allocated rather than before when there's a chance that the registration might still fail or to receive it with ifindex/NDA_MASTER == 0. Note that we can remove the fdb flush from br_vlan_flush() since that case can no longer happen. At NETDEV_REGISTER br->default_pvid is always == 1 as it's initialized by br_vlan_init() before that and at NETDEV_UNREGISTER it can be anything depending why it was called (if called due to NETDEV_REGISTER error it'll still be == 1, otherwise it could be any value changed during the device life time). For the demonstration below a small change to iproute2 for printing all fdb notifications is added, because it contained a workaround not to show entries with ifindex == 0. Command executed while monitoring: $ ip l add br0 type bridge Before (both ifindex and master == 0): $ bridge monitor fdb 36:7e:8a:b3:56:ba dev * vlan 1 master * permanent After (proper br0 ifindex): $ bridge monitor fdb e6:2a:ae:7a:b7:48 dev br0 vlan 1 master br0 permanent v4: move only the default pvid init/deinit to NETDEV_REGISTER/UNREGISTER v3: send the correct v2 patch with all changes (stub should return 0) v2: on error in br_vlan_init set br->vlgrp to NULL and return 0 in the br_vlan_bridge_event stub when bridge vlans are disabled [0] https://bugzilla.kernel.org/show_bug.cgi?id=204389 Reported-by: michael-dev <michael-dev at fami-braun.de> Fixes: 5be5a2df40f0 ("bridge: Add filtering support for default_pvid") Signed-off-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com> --- To test the patch I've added manual error conditions all over the bridge init process to exercise all of the error handling paths. This change is equivalent to v3 w.r.t. init ordering fixes, the core of the problem was the default pvid init/deinit sequences being done at wrong times, so we delay them until NETDEV_REGISTER/UNREGISTER. net/bridge/br.c | 5 ++++- net/bridge/br_private.h | 9 +++++---- net/bridge/br_vlan.c | 34 ++++++++++++++++------------------ 3 files changed, 25 insertions(+), 23 deletions(-) diff --git a/net/bridge/br.c b/net/bridge/br.c index d164f63a4345..8a8f9e5f264f 100644 --- a/net/bridge/br.c +++ b/net/bridge/br.c @@ -37,12 +37,15 @@ static int br_device_event(struct notifier_block *unused, unsigned long event, v int err; if (dev->priv_flags & IFF_EBRIDGE) { + err = br_vlan_bridge_event(dev, event, ptr); + if (err) + return notifier_from_errno(err); + if (event == NETDEV_REGISTER) { /* register of bridge completed, add sysfs entries */ br_sysfs_addbr(dev); return NOTIFY_DONE; } - br_vlan_bridge_event(dev, event, ptr); } /* not a port of a bridge */ diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index e8cf03b43b7d..646504db0220 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -894,8 +894,8 @@ int nbp_get_num_vlan_infos(struct net_bridge_port *p, u32 filter_mask); void br_vlan_get_stats(const struct net_bridge_vlan *v, struct br_vlan_stats *stats); void br_vlan_port_event(struct net_bridge_port *p, unsigned long event); -void br_vlan_bridge_event(struct net_device *dev, unsigned long event, - void *ptr); +int br_vlan_bridge_event(struct net_device *dev, unsigned long event, + void *ptr); static inline struct net_bridge_vlan_group *br_vlan_group( const struct net_bridge *br) @@ -1085,9 +1085,10 @@ static inline void br_vlan_port_event(struct net_bridge_port *p, { } -static inline void br_vlan_bridge_event(struct net_device *dev, - unsigned long event, void *ptr) +static inline int br_vlan_bridge_event(struct net_device *dev, + unsigned long event, void *ptr) { + return 0; } #endif diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c index a544e161c7fa..f5b2aeebbfe9 100644 --- a/net/bridge/br_vlan.c +++ b/net/bridge/br_vlan.c @@ -715,11 +715,6 @@ void br_vlan_flush(struct net_bridge *br) ASSERT_RTNL(); - /* delete auto-added default pvid local fdb before flushing vlans - * otherwise it will be leaked on bridge device init failure - */ - br_fdb_delete_by_port(br, NULL, 0, 1); - vg = br_vlan_group(br); __vlan_flush(vg); RCU_INIT_POINTER(br->vlgrp, NULL); @@ -1058,7 +1053,6 @@ int br_vlan_init(struct net_bridge *br) { struct net_bridge_vlan_group *vg; int ret = -ENOMEM; - bool changed; vg = kzalloc(sizeof(*vg), GFP_KERNEL); if (!vg) @@ -1073,17 +1067,10 @@ int br_vlan_init(struct net_bridge *br) br->vlan_proto = htons(ETH_P_8021Q); br->default_pvid = 1; rcu_assign_pointer(br->vlgrp, vg); - ret = br_vlan_add(br, 1, - BRIDGE_VLAN_INFO_PVID | BRIDGE_VLAN_INFO_UNTAGGED | - BRIDGE_VLAN_INFO_BRENTRY, &changed, NULL); - if (ret) - goto err_vlan_add; out: return ret; -err_vlan_add: - vlan_tunnel_deinit(vg); err_tunnel_init: rhashtable_destroy(&vg->vlan_hash); err_rhtbl: @@ -1469,13 +1456,23 @@ static void nbp_vlan_set_vlan_dev_state(struct net_bridge_port *p, u16 vid) } /* Must be protected by RTNL. */ -void br_vlan_bridge_event(struct net_device *dev, unsigned long event, - void *ptr) +int br_vlan_bridge_event(struct net_device *dev, unsigned long event, void *ptr) { struct netdev_notifier_changeupper_info *info; - struct net_bridge *br; + struct net_bridge *br = netdev_priv(dev); + bool changed; + int ret = 0; switch (event) { + case NETDEV_REGISTER: + ret = br_vlan_add(br, br->default_pvid, + BRIDGE_VLAN_INFO_PVID | + BRIDGE_VLAN_INFO_UNTAGGED | + BRIDGE_VLAN_INFO_BRENTRY, &changed, NULL); + break; + case NETDEV_UNREGISTER: + br_vlan_delete(br, br->default_pvid); + break; case NETDEV_CHANGEUPPER: info = ptr; br_vlan_upper_change(dev, info->upper_dev, info->linking); @@ -1483,12 +1480,13 @@ void br_vlan_bridge_event(struct net_device *dev, unsigned long event, case NETDEV_CHANGE: case NETDEV_UP: - br = netdev_priv(dev); if (!br_opt_get(br, BROPT_VLAN_BRIDGE_BINDING)) - return; + break; br_vlan_link_state_change(dev, br); break; } + + return ret; } /* Must be protected by RTNL. */ -- 2.21.0