Eric Dumazet wrote: > > On Fri, Aug 2, 2024 at 5:00 PM Jeongjun Park wrote: > > > > In do_setlink() , do_set_master() is called when dev->flags does not have > > the IFF_UP flag set, so 'team->lock' is acquired and dev_open() is called, > > which generates the NETDEV_UP event. This causes a deadlock as it tries to > > acquire 'team->lock' again. > > > > To fix this, we need to remove the unnecessary mutex_lock from all paths > > protected by rtnl. This patch also includes patches for paths that are > > already protected by rtnl and do not need the mutex_lock, in addition > > to the root cause reported. > > > > Reported-by: syzbot+b668da2bc4cb9670bf58@syzkaller.appspotmail.com > > Fixes: 61dc3461b954 ("team: convert overall spinlock to mutex") > > Signed-off-by: Jeongjun Park > > --- > > This can not be right. > > You have to completely remove team->lock, otherwise paths not taking > RTNL will race with ones holding RTNL. > > Add ASSERT_RTNL() at the places we had a  mutex_lock(&team->lock), and > see how it goes. Thanks for the advice. I've rewritten the patch to remove all mutex_lock as you suggested. I've also added checks for specific paths that don't use rtnl_lock. What do you think about patching it this way? Regards, Jeongjun Park --- drivers/net/team/team_core.c | 47 +++++++++--------------------------- include/linux/if_team.h | 4 +-- 2 files changed, 12 insertions(+), 39 deletions(-) diff --git a/drivers/net/team/team_core.c b/drivers/net/team/team_core.c index ab1935a4aa2c..1e2c631e3b78 100644 --- a/drivers/net/team/team_core.c +++ b/drivers/net/team/team_core.c @@ -1621,6 +1621,7 @@ static int team_init(struct net_device *dev) team->dev = dev; team_set_no_mode(team); team->notifier_ctx = false; + team->rtnl_locked = false; team->pcpu_stats = netdev_alloc_pcpu_stats(struct team_pcpu_stats); if (!team->pcpu_stats) @@ -1646,10 +1647,6 @@ static int team_init(struct net_device *dev) goto err_options_register; netif_carrier_off(dev); - lockdep_register_key(&team->team_lock_key); - __mutex_init(&team->lock, "team->team_lock_key", &team->team_lock_key); - netdev_lockdep_set_classes(dev); - return 0; err_options_register: @@ -1668,7 +1665,6 @@ static void team_uninit(struct net_device *dev) struct team_port *port; struct team_port *tmp; - mutex_lock(&team->lock); list_for_each_entry_safe(port, tmp, &team->port_list, list) team_port_del(team, port->dev); @@ -1677,9 +1673,7 @@ static void team_uninit(struct net_device *dev) team_mcast_rejoin_fini(team); team_notify_peers_fini(team); team_queue_override_fini(team); - mutex_unlock(&team->lock); netdev_change_features(dev); - lockdep_unregister_key(&team->team_lock_key); } static void team_destructor(struct net_device *dev) @@ -1800,11 +1794,9 @@ static int team_set_mac_address(struct net_device *dev, void *p) if (dev->type == ARPHRD_ETHER && !is_valid_ether_addr(addr->sa_data)) return -EADDRNOTAVAIL; dev_addr_set(dev, addr->sa_data); - mutex_lock(&team->lock); list_for_each_entry(port, &team->port_list, list) if (team->ops.port_change_dev_addr) team->ops.port_change_dev_addr(team, port); - mutex_unlock(&team->lock); return 0; } @@ -1818,7 +1810,6 @@ static int team_change_mtu(struct net_device *dev, int new_mtu) * Alhough this is reader, it's guarded by team lock. It's not possible * to traverse list in reverse under rcu_read_lock */ - mutex_lock(&team->lock); team->port_mtu_change_allowed = true; list_for_each_entry(port, &team->port_list, list) { err = dev_set_mtu(port->dev, new_mtu); @@ -1829,7 +1820,6 @@ static int team_change_mtu(struct net_device *dev, int new_mtu) } } team->port_mtu_change_allowed = false; - mutex_unlock(&team->lock); WRITE_ONCE(dev->mtu, new_mtu); @@ -1839,7 +1829,6 @@ static int team_change_mtu(struct net_device *dev, int new_mtu) list_for_each_entry_continue_reverse(port, &team->port_list, list) dev_set_mtu(port->dev, dev->mtu); team->port_mtu_change_allowed = false; - mutex_unlock(&team->lock); return err; } @@ -1893,20 +1882,17 @@ static int team_vlan_rx_add_vid(struct net_device *dev, __be16 proto, u16 vid) * Alhough this is reader, it's guarded by team lock. It's not possible * to traverse list in reverse under rcu_read_lock */ - mutex_lock(&team->lock); list_for_each_entry(port, &team->port_list, list) { err = vlan_vid_add(port->dev, proto, vid); if (err) goto unwind; } - mutex_unlock(&team->lock); return 0; unwind: list_for_each_entry_continue_reverse(port, &team->port_list, list) vlan_vid_del(port->dev, proto, vid); - mutex_unlock(&team->lock); return err; } @@ -1916,10 +1902,8 @@ static int team_vlan_rx_kill_vid(struct net_device *dev, __be16 proto, u16 vid) struct team *team = netdev_priv(dev); struct team_port *port; - mutex_lock(&team->lock); list_for_each_entry(port, &team->port_list, list) vlan_vid_del(port->dev, proto, vid); - mutex_unlock(&team->lock); return 0; } @@ -1941,9 +1925,7 @@ static void team_netpoll_cleanup(struct net_device *dev) { struct team *team = netdev_priv(dev); - mutex_lock(&team->lock); __team_netpoll_cleanup(team); - mutex_unlock(&team->lock); } static int team_netpoll_setup(struct net_device *dev, @@ -1953,7 +1935,6 @@ static int team_netpoll_setup(struct net_device *dev, struct team_port *port; int err = 0; - mutex_lock(&team->lock); list_for_each_entry(port, &team->port_list, list) { err = __team_port_enable_netpoll(port); if (err) { @@ -1961,7 +1942,6 @@ static int team_netpoll_setup(struct net_device *dev, break; } } - mutex_unlock(&team->lock); return err; } #endif @@ -1972,9 +1952,7 @@ static int team_add_slave(struct net_device *dev, struct net_device *port_dev, struct team *team = netdev_priv(dev); int err; - mutex_lock(&team->lock); err = team_port_add(team, port_dev, extack); - mutex_unlock(&team->lock); if (!err) netdev_change_features(dev); @@ -1987,18 +1965,11 @@ static int team_del_slave(struct net_device *dev, struct net_device *port_dev) struct team *team = netdev_priv(dev); int err; - mutex_lock(&team->lock); err = team_port_del(team, port_dev); - mutex_unlock(&team->lock); if (err) return err; - if (netif_is_team_master(port_dev)) { - lockdep_unregister_key(&team->team_lock_key); - lockdep_register_key(&team->team_lock_key); - lockdep_set_class(&team->lock, &team->team_lock_key); - } netdev_change_features(dev); return err; @@ -2305,13 +2276,11 @@ static struct team *team_nl_team_get(struct genl_info *info) } team = netdev_priv(dev); - mutex_lock(&team->lock); return team; } static void team_nl_team_put(struct team *team) { - mutex_unlock(&team->lock); dev_put(team->dev); } @@ -2501,6 +2470,11 @@ int team_nl_options_get_doit(struct sk_buff *skb, struct genl_info *info) int err; LIST_HEAD(sel_opt_inst_list); + if (!rtnl_is_locked()) { + rtnl_lock(); + team->rtnl_locked = true; + } + team = team_nl_team_get(info); if (!team) return -EINVAL; @@ -2513,6 +2487,11 @@ int team_nl_options_get_doit(struct sk_buff *skb, struct genl_info *info) team_nl_team_put(team); + if (team->rtnl_locked) { + team->rtnl_locked = false; + rtnl_unlock(); + } + return err; } @@ -2945,11 +2924,7 @@ static void __team_port_change_port_removed(struct team_port *port) static void team_port_change_check(struct team_port *port, bool linkup) { - struct team *team = port->team; - - mutex_lock(&team->lock); __team_port_change_check(port, linkup); - mutex_unlock(&team->lock); } diff --git a/include/linux/if_team.h b/include/linux/if_team.h index cdc684e04a2f..930c5deb4ad1 100644 --- a/include/linux/if_team.h +++ b/include/linux/if_team.h @@ -191,8 +191,6 @@ struct team { const struct header_ops *header_ops_cache; - struct mutex lock; /* used for overall locking, e.g. port lists write */ - /* * List of enabled ports and their count */ @@ -223,8 +221,8 @@ struct team { atomic_t count_pending; struct delayed_work dw; } mcast_rejoin; - struct lock_class_key team_lock_key; long mode_priv[TEAM_MODE_PRIV_LONGS]; + bool rtnl_locked; }; static inline int team_dev_queue_xmit(struct team *team, struct team_port *port, --