From ab92d68fc22f9afab480153bd82a20f6e2533769 Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Mon, 21 Oct 2019 18:47:51 +0000 Subject: net: core: add generic lockdep keys Some interface types could be nested. (VLAN, BONDING, TEAM, MACSEC, MACVLAN, IPVLAN, VIRT_WIFI, VXLAN, etc..) These interface types should set lockdep class because, without lockdep class key, lockdep always warn about unexisting circular locking. In the current code, these interfaces have their own lockdep class keys and these manage itself. So that there are so many duplicate code around the /driver/net and /net/. This patch adds new generic lockdep keys and some helper functions for it. This patch does below changes. a) Add lockdep class keys in struct net_device - qdisc_running, xmit, addr_list, qdisc_busylock - these keys are used as dynamic lockdep key. b) When net_device is being allocated, lockdep keys are registered. - alloc_netdev_mqs() c) When net_device is being free'd llockdep keys are unregistered. - free_netdev() d) Add generic lockdep key helper function - netdev_register_lockdep_key() - netdev_unregister_lockdep_key() - netdev_update_lockdep_key() e) Remove unnecessary generic lockdep macro and functions f) Remove unnecessary lockdep code of each interfaces. After this patch, each interface modules don't need to maintain their lockdep keys. Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller --- drivers/net/team/team.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'drivers/net/team') diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c index e8089def5a46..6cea83b48cad 100644 --- a/drivers/net/team/team.c +++ b/drivers/net/team/team.c @@ -1642,8 +1642,6 @@ static int team_init(struct net_device *dev) goto err_options_register; netif_carrier_off(dev); - netdev_lockdep_set_classes(dev); - return 0; err_options_register: -- cgit v1.2.3 From 369f61bee0f584aee09f0736431eb9b330c98571 Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Mon, 21 Oct 2019 18:47:54 +0000 Subject: team: fix nested locking lockdep warning team interface could be nested and it's lock variable could be nested too. But this lock uses static lockdep key and there is no nested locking handling code such as mutex_lock_nested() and so on. so the Lockdep would warn about the circular locking scenario that couldn't happen. In order to fix, this patch makes the team module to use dynamic lock key instead of static key. Test commands: ip link add team0 type team ip link add team1 type team ip link set team0 master team1 ip link set team0 nomaster ip link set team1 master team0 ip link set team1 nomaster Splat that looks like: [ 40.364352] WARNING: possible recursive locking detected [ 40.364964] 5.4.0-rc3+ #96 Not tainted [ 40.365405] -------------------------------------------- [ 40.365973] ip/750 is trying to acquire lock: [ 40.366542] ffff888060b34c40 (&team->lock){+.+.}, at: team_set_mac_address+0x151/0x290 [team] [ 40.367689] but task is already holding lock: [ 40.368729] ffff888051201c40 (&team->lock){+.+.}, at: team_del_slave+0x29/0x60 [team] [ 40.370280] other info that might help us debug this: [ 40.371159] Possible unsafe locking scenario: [ 40.371942] CPU0 [ 40.372338] ---- [ 40.372673] lock(&team->lock); [ 40.373115] lock(&team->lock); [ 40.373549] *** DEADLOCK *** [ 40.374432] May be due to missing lock nesting notation [ 40.375338] 2 locks held by ip/750: [ 40.375851] #0: ffffffffabcc42b0 (rtnl_mutex){+.+.}, at: rtnetlink_rcv_msg+0x466/0x8a0 [ 40.376927] #1: ffff888051201c40 (&team->lock){+.+.}, at: team_del_slave+0x29/0x60 [team] [ 40.377989] stack backtrace: [ 40.378650] CPU: 0 PID: 750 Comm: ip Not tainted 5.4.0-rc3+ #96 [ 40.379368] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 40.380574] Call Trace: [ 40.381208] dump_stack+0x7c/0xbb [ 40.381959] __lock_acquire+0x269d/0x3de0 [ 40.382817] ? register_lock_class+0x14d0/0x14d0 [ 40.383784] ? check_chain_key+0x236/0x5d0 [ 40.384518] lock_acquire+0x164/0x3b0 [ 40.385074] ? team_set_mac_address+0x151/0x290 [team] [ 40.385805] __mutex_lock+0x14d/0x14c0 [ 40.386371] ? team_set_mac_address+0x151/0x290 [team] [ 40.387038] ? team_set_mac_address+0x151/0x290 [team] [ 40.387632] ? mutex_lock_io_nested+0x1380/0x1380 [ 40.388245] ? team_del_slave+0x60/0x60 [team] [ 40.388752] ? rcu_read_lock_sched_held+0x90/0xc0 [ 40.389304] ? rcu_read_lock_bh_held+0xa0/0xa0 [ 40.389819] ? lock_acquire+0x164/0x3b0 [ 40.390285] ? lockdep_rtnl_is_held+0x16/0x20 [ 40.390797] ? team_port_get_rtnl+0x90/0xe0 [team] [ 40.391353] ? __module_text_address+0x13/0x140 [ 40.391886] ? team_set_mac_address+0x151/0x290 [team] [ 40.392547] team_set_mac_address+0x151/0x290 [team] [ 40.393111] dev_set_mac_address+0x1f0/0x3f0 [ ... ] Fixes: 3d249d4ca7d0 ("net: introduce ethernet teaming device") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller --- drivers/net/team/team.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'drivers/net/team') diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c index 6cea83b48cad..8156b33ee3e7 100644 --- a/drivers/net/team/team.c +++ b/drivers/net/team/team.c @@ -1615,7 +1615,6 @@ static int team_init(struct net_device *dev) int err; team->dev = dev; - mutex_init(&team->lock); team_set_no_mode(team); team->pcpu_stats = netdev_alloc_pcpu_stats(struct team_pcpu_stats); @@ -1642,6 +1641,9 @@ 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); + return 0; err_options_register: @@ -1671,6 +1673,7 @@ static void team_uninit(struct net_device *dev) 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) @@ -1974,8 +1977,15 @@ static int team_del_slave(struct net_device *dev, struct net_device *port_dev) err = team_port_del(team, port_dev); mutex_unlock(&team->lock); - if (!err) - netdev_change_features(dev); + 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; } -- cgit v1.2.3