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From: Divyesh Shah <dpshah@google.com>
Date: Thu, 10 Jun 2010 18:33:08 -0700
Message-ID: <AANLkTinzd3TDVInveyx1P1ATvV8QaudtTsU0ofzclpuk@mail.gmail.com>
Subject: Re: blkiocg_update_io_add_stats(): INFO: trying to register 
	non-static key
To: Jens Axboe <jaxboe@fusionio.com>
Cc: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
       piotr@hosowicz.com, linux-kernel@vger.kernel.org
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On Wed, Jun 2, 2010 at 6:04 AM, Jens Axboe <jaxboe@fusionio.com> wrote:
> On Wed, Jun 02 2010, Ingo Molnar wrote:
>>
>> btw., there's another warning triggered by the new blk-cgroups stats code:
>>
>> sda:INFO: trying to register non-static key.
>> the code is fine but needs lockdep annotation.
>> turning off the locking correctness validator.
>> Pid: 81, comm: async/2 Not tainted 2.6.35-rc1-tip-01073-gd2f7698-dirty #6765
>> Call Trace:
>> ?[<ffffffff81065d6d>] register_lock_class+0x15f/0x365
>> ?[<ffffffff8105c426>] ? sched_clock_local+0x1d/0x83
>> ?[<ffffffff8105c557>] ? sched_clock_cpu+0xcb/0xd9
>> ?[<ffffffff81067184>] __lock_acquire+0x97/0x481
>> ?[<ffffffff810088d4>] ? native_sched_clock+0x37/0x6d
>> ?[<ffffffff81321b74>] ? blkiocg_update_io_add_stats+0x32/0x12e
>> ?[<ffffffff81067644>] lock_acquire+0xd6/0xfd
>> ?[<ffffffff81321b74>] ? blkiocg_update_io_add_stats+0x32/0x12e
>> ?[<ffffffff81850859>] _raw_spin_lock_irqsave+0x47/0x82
>> ?[<ffffffff81321b74>] ? blkiocg_update_io_add_stats+0x32/0x12e
>> ?[<ffffffff81321b74>] blkiocg_update_io_add_stats+0x32/0x12e
>
> So that's blkg->stats_lock - help me out, what is lockdep complaining
> about? The lock is initialized, what kind of lockdep annotation magic do
> we need to sprinkle on it?

Jens,
     Were you able to figure out what annotation magic is needed here.
I remember we had fixed another similar warning that Gui reported, but
that was because the root cfqg didn't have the stats_lock initialized
as expected. I'm not sure what needs to be done here either.

-Divyesh

>
> --
> Jens Axboe
>
>
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