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 <ap420073@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index e7a8722..ce85656 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -71,6 +71,7 @@ ax25_address rose_callsign;
* separate class since they always nest.
*/
static struct lock_class_key rose_netdev_xmit_lock_key;
+static struct lock_class_key rose_netdev_addr_lock_key;
static void rose_set_lockdep_one(struct net_device *dev,
struct netdev_queue *txq,
@@ -81,6 +82,7 @@ static void rose_set_lockdep_one(struct net_device *dev,
static void rose_set_lockdep_key(struct net_device *dev)
{
+ lockdep_set_class(&dev->addr_list_lock, &rose_netdev_addr_lock_key);
netdev_for_each_tx_queue(dev, rose_set_lockdep_one, NULL);
}