workqueue, pci: INFO: possible recursive locking detected

From: Srivatsa S. Bhat
Date: Tue Jul 16 2013 - 10:44:39 EST


Hi,

I have been seeing this warning every time during boot. I haven't
spent time digging through it though... Please let me know if
any machine-specific info is needed.

Regards,
Srivatsa S. Bhat


----------------------------------------------------

=============================================
[ INFO: possible recursive locking detected ]
3.11.0-rc1-lockdep-fix-a #6 Not tainted
---------------------------------------------
kworker/0:1/142 is trying to acquire lock:
((&wfc.work)){+.+.+.}, at: [<ffffffff81077100>] flush_work+0x0/0xb0

but task is already holding lock:
((&wfc.work)){+.+.+.}, at: [<ffffffff81075dd9>] process_one_work+0x169/0x610

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock((&wfc.work));
lock((&wfc.work));

*** DEADLOCK ***

May be due to missing lock nesting notation

3 locks held by kworker/0:1/142:
#0: (events){.+.+.+}, at: [<ffffffff81075dd9>] process_one_work+0x169/0x610
#1: ((&wfc.work)){+.+.+.}, at: [<ffffffff81075dd9>] process_one_work+0x169/0x610
#2: (&__lockdep_no_validate__){......}, at: [<ffffffff8139a3ba>] device_attach+0x2a/0xc0

stack backtrace:
CPU: 0 PID: 142 Comm: kworker/0:1 Not tainted 3.11.0-rc1-lockdep-fix-a #6
Hardware name: IBM -[8737R2A]-/00Y2738, BIOS -[B2E120RUS-1.20]- 11/30/2012
Workqueue: events work_for_cpu_fn
ffff881036fecd88 ffff881036fef678 ffffffff8161a919 0000000000000003
ffff881036fec400 ffff881036fef6a8 ffffffff810c2234 ffff881036fec400
ffff881036fecd88 ffff881036fec400 0000000000000000 ffff881036fef708
Call Trace:
[<ffffffff8161a919>] dump_stack+0x59/0x80
[<ffffffff810c2234>] print_deadlock_bug+0xf4/0x100
[<ffffffff810c3d14>] validate_chain+0x504/0x750
[<ffffffff810c426d>] __lock_acquire+0x30d/0x580
[<ffffffff810c4577>] lock_acquire+0x97/0x170
[<ffffffff81077100>] ? start_flush_work+0x220/0x220
[<ffffffff81077148>] flush_work+0x48/0xb0
[<ffffffff81077100>] ? start_flush_work+0x220/0x220
[<ffffffff810c2c10>] ? mark_held_locks+0x80/0x130
[<ffffffff81074cfb>] ? queue_work_on+0x4b/0xa0
[<ffffffff810c2f85>] ? trace_hardirqs_on_caller+0x105/0x1d0
[<ffffffff810c305d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff81077320>] work_on_cpu+0x80/0x90
[<ffffffff8106f950>] ? wqattrs_hash+0x190/0x190
[<ffffffff812d37b0>] ? pci_pm_prepare+0x60/0x60
[<ffffffff812a0059>] ? cpumask_next_and+0x29/0x50
[<ffffffff812d38da>] __pci_device_probe+0x9a/0xe0
[<ffffffff81620850>] ? _raw_spin_unlock_irq+0x30/0x50
[<ffffffff812d4be2>] ? pci_dev_get+0x22/0x30
[<ffffffff812d4c2a>] pci_device_probe+0x3a/0x60
[<ffffffff81620850>] ? _raw_spin_unlock_irq+0x30/0x50
[<ffffffff8139a4bc>] really_probe+0x6c/0x320
[<ffffffff8139a7b7>] driver_probe_device+0x47/0xa0
[<ffffffff8139a8c0>] ? __driver_attach+0xb0/0xb0
[<ffffffff8139a913>] __device_attach+0x53/0x60
[<ffffffff81398404>] bus_for_each_drv+0x74/0xa0
[<ffffffff8139a430>] device_attach+0xa0/0xc0
[<ffffffff812cb2d9>] pci_bus_add_device+0x39/0x60
[<ffffffff812eec21>] virtfn_add+0x251/0x3e0
[<ffffffff810c305d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff812ef29f>] sriov_enable+0x22f/0x3d0
[<ffffffff812ef48d>] pci_enable_sriov+0x4d/0x60
[<ffffffffa0143045>] be_vf_setup+0x175/0x410 [be2net]
[<ffffffffa01493ca>] be_setup+0x37a/0x4b0 [be2net]
[<ffffffffa0149ac0>] be_probe+0x5c0/0x820 [be2net]
[<ffffffff812d37fe>] local_pci_probe+0x4e/0x90
[<ffffffff8106f968>] work_for_cpu_fn+0x18/0x30
[<ffffffff81075e4a>] process_one_work+0x1da/0x610
[<ffffffff81075dd9>] ? process_one_work+0x169/0x610
[<ffffffff8107650c>] worker_thread+0x28c/0x3a0
[<ffffffff81076280>] ? process_one_work+0x610/0x610
[<ffffffff8107da3e>] kthread+0xee/0x100
[<ffffffff8107d950>] ? __init_kthread_worker+0x70/0x70
[<ffffffff8162a71c>] ret_from_fork+0x7c/0xb0
[<ffffffff8107d950>] ? __init_kthread_worker+0x70/0x70

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