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authorCong Wang <xiyou.wangcong@gmail.com>2020-06-09 00:53:01 +0300
committerDavid S. Miller <davem@davemloft.net>2020-06-09 22:59:45 +0300
commit845e0ebb4408d4473cf60d21224a897037e9a77a (patch)
tree053282d21248269b50668f920d39ba07b7a0277d /net/dsa
parent8027bc0307ce59759b90679fa5d8b22949586d20 (diff)
downloadlinux-845e0ebb4408d4473cf60d21224a897037e9a77a.tar.xz
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>
Diffstat (limited to 'net/dsa')
-rw-r--r--net/dsa/master.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/dsa/master.c b/net/dsa/master.c
index a621367c6e8c..480a61460c23 100644
--- a/net/dsa/master.c
+++ b/net/dsa/master.c
@@ -327,6 +327,8 @@ static void dsa_master_reset_mtu(struct net_device *dev)
rtnl_unlock();
}
+static struct lock_class_key dsa_master_addr_list_lock_key;
+
int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
{
int ret;
@@ -345,6 +347,8 @@ int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp)
wmb();
dev->dsa_ptr = cpu_dp;
+ lockdep_set_class(&dev->addr_list_lock,
+ &dsa_master_addr_list_lock_key);
ret = dsa_master_ethtool_setup(dev);
if (ret)
return ret;