linux/net/core
dingtianhong dc8eaaa006 vlan: Fix lockdep warning when vlan dev handle notification
When I open the LOCKDEP config and run these steps:

modprobe 8021q
vconfig add eth2 20
vconfig add eth2.20 30
ifconfig eth2 xx.xx.xx.xx

then the Call Trace happened:

[32524.386288] =============================================
[32524.386293] [ INFO: possible recursive locking detected ]
[32524.386298] 3.14.0-rc2-0.7-default+ #35 Tainted: G           O
[32524.386302] ---------------------------------------------
[32524.386306] ifconfig/3103 is trying to acquire lock:
[32524.386310]  (&vlan_netdev_addr_lock_key/1){+.....}, at: [<ffffffff814275f4>] dev_mc_sync+0x64/0xb0
[32524.386326]
[32524.386326] but task is already holding lock:
[32524.386330]  (&vlan_netdev_addr_lock_key/1){+.....}, at: [<ffffffff8141af83>] dev_set_rx_mode+0x23/0x40
[32524.386341]
[32524.386341] other info that might help us debug this:
[32524.386345]  Possible unsafe locking scenario:
[32524.386345]
[32524.386350]        CPU0
[32524.386352]        ----
[32524.386354]   lock(&vlan_netdev_addr_lock_key/1);
[32524.386359]   lock(&vlan_netdev_addr_lock_key/1);
[32524.386364]
[32524.386364]  *** DEADLOCK ***
[32524.386364]
[32524.386368]  May be due to missing lock nesting notation
[32524.386368]
[32524.386373] 2 locks held by ifconfig/3103:
[32524.386376]  #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff81431d42>] rtnl_lock+0x12/0x20
[32524.386387]  #1:  (&vlan_netdev_addr_lock_key/1){+.....}, at: [<ffffffff8141af83>] dev_set_rx_mode+0x23/0x40
[32524.386398]
[32524.386398] stack backtrace:
[32524.386403] CPU: 1 PID: 3103 Comm: ifconfig Tainted: G           O 3.14.0-rc2-0.7-default+ #35
[32524.386409] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[32524.386414]  ffffffff81ffae40 ffff8800d9625ae8 ffffffff814f68a2 ffff8800d9625bc8
[32524.386421]  ffffffff810a35fb ffff8800d8a8d9d0 00000000d9625b28 ffff8800d8a8e5d0
[32524.386428]  000003cc00000000 0000000000000002 ffff8800d8a8e5f8 0000000000000000
[32524.386435] Call Trace:
[32524.386441]  [<ffffffff814f68a2>] dump_stack+0x6a/0x78
[32524.386448]  [<ffffffff810a35fb>] __lock_acquire+0x7ab/0x1940
[32524.386454]  [<ffffffff810a323a>] ? __lock_acquire+0x3ea/0x1940
[32524.386459]  [<ffffffff810a4874>] lock_acquire+0xe4/0x110
[32524.386464]  [<ffffffff814275f4>] ? dev_mc_sync+0x64/0xb0
[32524.386471]  [<ffffffff814fc07a>] _raw_spin_lock_nested+0x2a/0x40
[32524.386476]  [<ffffffff814275f4>] ? dev_mc_sync+0x64/0xb0
[32524.386481]  [<ffffffff814275f4>] dev_mc_sync+0x64/0xb0
[32524.386489]  [<ffffffffa0500cab>] vlan_dev_set_rx_mode+0x2b/0x50 [8021q]
[32524.386495]  [<ffffffff8141addf>] __dev_set_rx_mode+0x5f/0xb0
[32524.386500]  [<ffffffff8141af8b>] dev_set_rx_mode+0x2b/0x40
[32524.386506]  [<ffffffff8141b3cf>] __dev_open+0xef/0x150
[32524.386511]  [<ffffffff8141b177>] __dev_change_flags+0xa7/0x190
[32524.386516]  [<ffffffff8141b292>] dev_change_flags+0x32/0x80
[32524.386524]  [<ffffffff8149ca56>] devinet_ioctl+0x7d6/0x830
[32524.386532]  [<ffffffff81437b0b>] ? dev_ioctl+0x34b/0x660
[32524.386540]  [<ffffffff814a05b0>] inet_ioctl+0x80/0xa0
[32524.386550]  [<ffffffff8140199d>] sock_do_ioctl+0x2d/0x60
[32524.386558]  [<ffffffff81401a52>] sock_ioctl+0x82/0x2a0
[32524.386568]  [<ffffffff811a7123>] do_vfs_ioctl+0x93/0x590
[32524.386578]  [<ffffffff811b2705>] ? rcu_read_lock_held+0x45/0x50
[32524.386586]  [<ffffffff811b39e5>] ? __fget_light+0x105/0x110
[32524.386594]  [<ffffffff811a76b1>] SyS_ioctl+0x91/0xb0
[32524.386604]  [<ffffffff815057e2>] system_call_fastpath+0x16/0x1b

========================================================================

The reason is that all of the addr_lock_key for vlan dev have the same class,
so if we change the status for vlan dev, the vlan dev and its real dev will
hold the same class of addr_lock_key together, so the warning happened.

we should distinguish the lock depth for vlan dev and its real dev.

v1->v2: Convert the vlan_netdev_addr_lock_key to an array of eight elements, which
	could support to add 8 vlan id on a same vlan dev, I think it is enough for current
	scene, because a netdev's name is limited to IFNAMSIZ which could not hold 8 vlan id,
	and the vlan dev would not meet the same class key with its real dev.

	The new function vlan_dev_get_lockdep_subkey() will return the subkey and make the vlan
	dev could get a suitable class key.

v2->v3: According David's suggestion, I use the subclass to distinguish the lock key for vlan dev
	and its real dev, but it make no sense, because the difference for subclass in the
	lock_class_key doesn't mean that the difference class for lock_key, so I use lock_depth
	to distinguish the different depth for every vlan dev, the same depth of the vlan dev
	could have the same lock_class_key, I import the MAX_LOCK_DEPTH from the include/linux/sched.h,
	I think it is enough here, the lockdep should never exceed that value.

v3->v4: Add a huge array of locking keys will waste static kernel memory and is not a appropriate method,
	we could use _nested() variants to fix the problem, calculate the depth for every vlan dev,
	and use the depth as the subclass for addr_lock_key.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-04-18 17:48:30 -04:00
..
Makefile net: ptp: move PTP classifier in its own file 2014-04-01 16:43:18 -04:00
datagram.c net, datagram: fix the incorrect comment in zerocopy_sg_from_iovec() 2013-10-29 00:19:04 -04:00
dev.c vlan: Fix lockdep warning when vlan dev handle notification 2014-04-18 17:48:30 -04:00
dev_addr_lists.c net: Correctly sync addresses from multiple sources to single device 2014-01-23 13:06:34 -08:00
dev_ioctl.c net_tstamp: Add SIOCGHWTSTAMP ioctl to match SIOCSHWTSTAMP 2013-11-19 19:07:21 +00:00
drop_monitor.c net: drop_monitor: fix the value of maxattr 2013-12-09 21:10:38 -05:00
dst.c ipv4: add a sock pointer to dst->output() path. 2014-04-15 13:47:15 -04:00
ethtool.c net: add busy_poll device feature 2014-04-03 14:31:34 -04:00
fib_rules.c net: fix 'ip rule' iif/oif device rename 2014-02-09 19:02:52 -08:00
filter.c net: filter: seccomp: fix wrong decoding of BPF_S_ANC_SECCOMP_LD_W 2014-04-14 16:26:47 -04:00
flow.c CPU hotplug notifiers registration fixes for 3.15-rc1 2014-04-07 14:55:46 -07:00
flow_dissector.c net: Rename skb->rxhash to skb->hash 2014-03-26 15:58:20 -04:00
gen_estimator.c net_sched: add 64bit rate estimators 2013-06-11 02:51:03 -07:00
gen_stats.c net_sched: add 64bit rate estimators 2013-06-11 02:51:03 -07:00
iovec.c net: rework recvmsg handler msg_name and msg_namelen logic 2013-11-20 21:52:30 -05:00
link_watch.c net: make all team port device link events urgent 2013-06-13 02:31:41 -07:00
neighbour.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-03-05 20:32:02 -05:00
net-procfs.c rps: selective flow shedding during softnet overflow 2013-05-20 13:48:04 -07:00
net-sysfs.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2014-04-02 20:53:45 -07:00
net-sysfs.h net: netdev_kobject_init: annotate with __init 2014-01-05 20:27:54 -05:00
net-traces.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
net_namespace.c userns: Kill nsown_capable it makes the wrong thing easy 2013-08-30 23:44:11 -07:00
netclassid_cgroup.c cgroup: drop @skip_css from cgroup_taskset_for_each() 2014-02-13 06:58:41 -05:00
netevent.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
netpoll.c netpoll: Use skb_irq_freeable to make zap_completion_queue safe. 2014-04-01 17:53:36 -04:00
netprio_cgroup.c cgroup: drop const from @buffer of cftype->write_string() 2014-03-19 10:23:54 -04:00
pktgen.c pktgen: be friendly to LLTX devices 2014-04-12 01:59:38 -04:00
ptp_classifier.c net: ptp: move PTP classifier in its own file 2014-04-01 16:43:18 -04:00
request_sock.c net: remove unnecessary return's 2014-02-13 18:33:38 -05:00
rtnetlink.c net-sysfs: expose number of carrier on/off changes 2014-03-31 16:24:52 -04:00
scm.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-09-07 14:35:32 -07:00
secure_seq.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2013-10-23 16:49:34 -04:00
skbuff.c net: Fix use after free by removing length arg from sk_data_ready callbacks. 2014-04-11 16:15:36 -04:00
sock.c net: Fix use after free by removing length arg from sk_data_ready callbacks. 2014-04-11 16:15:36 -04:00
sock_diag.c net: filter: keep original BPF program around 2014-03-31 00:45:09 -04:00
stream.c net: replace macros net_random and net_srandom with direct calls to prandom 2014-01-14 15:15:25 -08:00
sysctl_net_core.c rps: NUMA flow limit allocations 2013-12-19 19:00:07 -05:00
timestamping.c net: ptp: move PTP classifier in its own file 2014-04-01 16:43:18 -04:00
user_dma.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
utils.c net: make net_get_random_once irq safe 2013-10-25 19:03:39 -04:00