From e9c953eff7f0ec69a52cfa87b912ab48902a0314 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Mon, 12 Oct 2015 21:47:03 +0200 Subject: [PATCH] bridge: vlan: use rcu for vlan_list traversal in br_fill_ifinfo br_fill_ifinfo is called by br_ifinfo_notify which can be called from many contexts with different locks held, sometimes it relies upon bridge's spinlock only which is a problem for the vlan code, so use explicitly rcu for that to avoid problems. Signed-off-by: Nikolay Aleksandrov Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller --- net/bridge/br_netlink.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 2ee8fd63c726..94b4de8c4646 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -253,7 +253,7 @@ static int br_fill_ifvlaninfo_compressed(struct sk_buff *skb, * if vlaninfo represents a range */ pvid = br_get_pvid(vg); - list_for_each_entry(v, &vg->vlan_list, vlist) { + list_for_each_entry_rcu(v, &vg->vlan_list, vlist) { flags = 0; if (!br_vlan_should_use(v)) continue; @@ -303,7 +303,7 @@ static int br_fill_ifvlaninfo(struct sk_buff *skb, u16 pvid; pvid = br_get_pvid(vg); - list_for_each_entry(v, &vg->vlan_list, vlist) { + list_for_each_entry_rcu(v, &vg->vlan_list, vlist) { if (!br_vlan_should_use(v)) continue; @@ -386,22 +386,27 @@ static int br_fill_ifinfo(struct sk_buff *skb, struct nlattr *af; int err; + /* RCU needed because of the VLAN locking rules (rcu || rtnl) */ + rcu_read_lock(); if (port) - vg = nbp_vlan_group(port); + vg = nbp_vlan_group_rcu(port); else - vg = br_vlan_group(br); + vg = br_vlan_group_rcu(br); - if (!vg || !vg->num_vlans) + if (!vg || !vg->num_vlans) { + rcu_read_unlock(); goto done; - + } af = nla_nest_start(skb, IFLA_AF_SPEC); - if (!af) + if (!af) { + rcu_read_unlock(); goto nla_put_failure; - + } if (filter_mask & RTEXT_FILTER_BRVLAN_COMPRESSED) err = br_fill_ifvlaninfo_compressed(skb, vg); else err = br_fill_ifvlaninfo(skb, vg); + rcu_read_unlock(); if (err) goto nla_put_failure; nla_nest_end(skb, af);