From 4f2c6ae5c64c353fb1b0425e4747e5603feadba1 Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Wed, 27 Jan 2016 15:16:43 +0100 Subject: switchdev: Require RTNL mutex to be held when sending FDB notifications When switchdev drivers process FDB notifications from the underlying device they resolve the netdev to which the entry points to and notify the bridge using the switchdev notifier. However, since the RTNL mutex is not held there is nothing preventing the netdev from disappearing in the middle, which will cause br_switchdev_event() to dereference a non-existing netdev. Make switchdev drivers hold the lock at the beginning of the notification processing session and release it once it ends, after notifying the bridge. Also, remove switchdev_mutex and fdb_lock, as they are no longer needed when RTNL mutex is held. Fixes: 03bf0c281234 ("switchdev: introduce switchdev notifier") Signed-off-by: Ido Schimmel Signed-off-by: Jiri Pirko Signed-off-by: David S. Miller --- net/switchdev/switchdev.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) (limited to 'net/switchdev/switchdev.c') diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c index ebc661d3b6e3..47f7da58a7f0 100644 --- a/net/switchdev/switchdev.c +++ b/net/switchdev/switchdev.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include @@ -567,7 +568,6 @@ int switchdev_port_obj_dump(struct net_device *dev, struct switchdev_obj *obj, } EXPORT_SYMBOL_GPL(switchdev_port_obj_dump); -static DEFINE_MUTEX(switchdev_mutex); static RAW_NOTIFIER_HEAD(switchdev_notif_chain); /** @@ -582,9 +582,9 @@ int register_switchdev_notifier(struct notifier_block *nb) { int err; - mutex_lock(&switchdev_mutex); + rtnl_lock(); err = raw_notifier_chain_register(&switchdev_notif_chain, nb); - mutex_unlock(&switchdev_mutex); + rtnl_unlock(); return err; } EXPORT_SYMBOL_GPL(register_switchdev_notifier); @@ -600,9 +600,9 @@ int unregister_switchdev_notifier(struct notifier_block *nb) { int err; - mutex_lock(&switchdev_mutex); + rtnl_lock(); err = raw_notifier_chain_unregister(&switchdev_notif_chain, nb); - mutex_unlock(&switchdev_mutex); + rtnl_unlock(); return err; } EXPORT_SYMBOL_GPL(unregister_switchdev_notifier); @@ -616,16 +616,17 @@ EXPORT_SYMBOL_GPL(unregister_switchdev_notifier); * Call all network notifier blocks. This should be called by driver * when it needs to propagate hardware event. * Return values are same as for atomic_notifier_call_chain(). + * rtnl_lock must be held. */ int call_switchdev_notifiers(unsigned long val, struct net_device *dev, struct switchdev_notifier_info *info) { int err; + ASSERT_RTNL(); + info->dev = dev; - mutex_lock(&switchdev_mutex); err = raw_notifier_call_chain(&switchdev_notif_chain, val, info); - mutex_unlock(&switchdev_mutex); return err; } EXPORT_SYMBOL_GPL(call_switchdev_notifiers); -- cgit v1.2.3 From 472681d57a5dde7c6d16b05469be57f1c4ed9d99 Mon Sep 17 00:00:00 2001 From: MINOURA Makoto / 箕浦 真 Date: Thu, 25 Feb 2016 14:20:48 +0900 Subject: net: ndo_fdb_dump should report -EMSGSIZE to rtnl_fdb_dump. When the send skbuff reaches the end, nlmsg_put and friends returns -EMSGSIZE but it is silently thrown away in ndo_fdb_dump. It is called within a for_each_netdev loop and the first fdb entry of a following netdev could fit in the remaining skbuff. This breaks the mechanism of cb->args[0] and idx to keep track of the entries that are already dumped, which results missing entries in bridge fdb show command. Signed-off-by: Minoura Makoto Signed-off-by: David S. Miller --- drivers/net/vxlan.c | 4 +++- net/bridge/br_fdb.c | 15 ++++++++++----- net/core/rtnetlink.c | 6 ++++++ net/switchdev/switchdev.c | 5 ++++- 4 files changed, 23 insertions(+), 7 deletions(-) (limited to 'net/switchdev/switchdev.c') diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index e6944b29588e..b601139a145a 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -931,8 +931,10 @@ static int vxlan_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb, cb->nlh->nlmsg_seq, RTM_NEWNEIGH, NLM_F_MULTI, rd); - if (err < 0) + if (err < 0) { + cb->args[1] = err; goto out; + } skip: ++idx; } diff --git a/net/bridge/br_fdb.c b/net/bridge/br_fdb.c index 82e3e9705017..dcea4f4c62b3 100644 --- a/net/bridge/br_fdb.c +++ b/net/bridge/br_fdb.c @@ -723,6 +723,8 @@ int br_fdb_dump(struct sk_buff *skb, struct net_bridge_fdb_entry *f; hlist_for_each_entry_rcu(f, &br->hash[i], hlist) { + int err; + if (idx < cb->args[0]) goto skip; @@ -741,12 +743,15 @@ int br_fdb_dump(struct sk_buff *skb, if (!filter_dev && f->dst) goto skip; - if (fdb_fill_info(skb, br, f, - NETLINK_CB(cb->skb).portid, - cb->nlh->nlmsg_seq, - RTM_NEWNEIGH, - NLM_F_MULTI) < 0) + err = fdb_fill_info(skb, br, f, + NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, + RTM_NEWNEIGH, + NLM_F_MULTI); + if (err < 0) { + cb->args[1] = err; break; + } skip: ++idx; } diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index d735e854f916..8261d95dd846 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2911,6 +2911,7 @@ int ndo_dflt_fdb_dump(struct sk_buff *skb, nlmsg_populate_fdb(skb, cb, dev, &idx, &dev->mc); out: netif_addr_unlock_bh(dev); + cb->args[1] = err; return idx; } EXPORT_SYMBOL(ndo_dflt_fdb_dump); @@ -2944,6 +2945,7 @@ static int rtnl_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb) ops = br_dev->netdev_ops; } + cb->args[1] = 0; for_each_netdev(net, dev) { if (brport_idx && (dev->ifindex != brport_idx)) continue; @@ -2971,12 +2973,16 @@ static int rtnl_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb) idx = cops->ndo_fdb_dump(skb, cb, br_dev, dev, idx); } + if (cb->args[1] == -EMSGSIZE) + break; if (dev->netdev_ops->ndo_fdb_dump) idx = dev->netdev_ops->ndo_fdb_dump(skb, cb, dev, NULL, idx); else idx = ndo_dflt_fdb_dump(skb, cb, dev, NULL, idx); + if (cb->args[1] == -EMSGSIZE) + break; cops = NULL; } diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c index 47f7da58a7f0..8b5833c1ff2e 100644 --- a/net/switchdev/switchdev.c +++ b/net/switchdev/switchdev.c @@ -1093,8 +1093,11 @@ int switchdev_port_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb, .cb = cb, .idx = idx, }; + int err; - switchdev_port_obj_dump(dev, &dump.fdb.obj, switchdev_port_fdb_dump_cb); + err = switchdev_port_obj_dump(dev, &dump.fdb.obj, + switchdev_port_fdb_dump_cb); + cb->args[1] = err; return dump.idx; } EXPORT_SYMBOL_GPL(switchdev_port_fdb_dump); -- cgit v1.2.3