From 845e0ebb4408d4473cf60d21224a897037e9a77a Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Mon, 8 Jun 2020 14:53:01 -0700 Subject: net: change addr_list_lock back to static key The dynamic key update for addr_list_lock still causes troubles, for example the following race condition still exists: CPU 0: CPU 1: (RCU read lock) (RTNL lock) dev_mc_seq_show() netdev_update_lockdep_key() -> lockdep_unregister_key() -> netif_addr_lock_bh() because lockdep doesn't provide an API to update it atomically. Therefore, we have to move it back to static keys and use subclass for nest locking like before. In commit 1a33e10e4a95 ("net: partially revert dynamic lockdep key changes"), I already reverted most parts of commit ab92d68fc22f ("net: core: add generic lockdep keys"). This patch reverts the rest and also part of commit f3b0a18bb6cb ("net: remove unnecessary variables and callback"). After this patch, addr_list_lock changes back to using static keys and subclasses to satisfy lockdep. Thanks to dev->lower_level, we do not have to change back to ->ndo_get_lock_subclass(). And hopefully this reduces some syzbot lockdep noises too. Reported-by: syzbot+f3a0e80c34b3fc28ac5e@syzkaller.appspotmail.com Cc: Taehee Yoo Cc: Dmitry Vyukov Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/bridge/br_device.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'net/bridge/br_device.c') diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c index 8ec1362588af..8c7b78f8bc23 100644 --- a/net/bridge/br_device.c +++ b/net/bridge/br_device.c @@ -105,6 +105,13 @@ out: return NETDEV_TX_OK; } +static struct lock_class_key bridge_netdev_addr_lock_key; + +static void br_set_lockdep_class(struct net_device *dev) +{ + lockdep_set_class(&dev->addr_list_lock, &bridge_netdev_addr_lock_key); +} + static int br_dev_init(struct net_device *dev) { struct net_bridge *br = netdev_priv(dev); @@ -143,6 +150,7 @@ static int br_dev_init(struct net_device *dev) br_fdb_hash_fini(br); } + br_set_lockdep_class(dev); return err; } -- cgit v1.2.3