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net: change addr_list_lock back to static key

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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 1a33e10e4a ("net: partially revert dynamic lockdep key
changes"), I already reverted most parts of commit ab92d68fc2
("net: core: add generic lockdep keys").

This patch reverts the rest and also part of commit f3b0a18bb6
("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>
This commit is contained in:
Cong Wang
2020-06-08 14:53:01 -07:00
committed by David S. Miller
parent 8027bc0307
commit 845e0ebb44
17 changed files with 76 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
net/netrom/af_netrom.c
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@@ -70,6 +70,7 @@ static const struct proto_ops nr_proto_ops;
* separate class since they always nest.
*/
static struct lock_class_key nr_netdev_xmit_lock_key;
static struct lock_class_key nr_netdev_addr_lock_key;
static void nr_set_lockdep_one(struct net_device *dev,
struct netdev_queue *txq,
@@ -80,6 +81,7 @@ static void nr_set_lockdep_one(struct net_device *dev,
static void nr_set_lockdep_key(struct net_device *dev)
{
lockdep_set_class(&dev->addr_list_lock, &nr_netdev_addr_lock_key);
netdev_for_each_tx_queue(dev, nr_set_lockdep_one, NULL);
}