linux-kernel - Re: odd lockdep messages

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Message-ID: <6025.1268078410@localhost>
Date:	Mon, 08 Mar 2010 15:00:10 -0500
From:	Valdis.Kletnieks@...edu
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	Tejun Heo <tj@...nel.org>
Subject: Re: odd lockdep messages

On Mon, 08 Mar 2010 19:43:51 +0100, Peter Zijlstra said:
> On Mon, 2010-03-08 at 13:30 -0500, Valdis.Kletnieks@...edu wrote:
> > (Not sure when this started, just noticed it... Wasn't present in
> > 2.6.33-rc7-mmotm0210, is in 2.6.33-mmotm0302 and -mmotm0304).
> > 
> > Seen in dmesg:

> > [    1.012163] BUG: key ffff88011efbf500 not in .data!
> > [    1.012284] BUG: key ffff88011efbf548 not in .data!

> Can that be wreckage due to the new per-cpu stuff?
> 
> Its a message printed when the below function fails, and that per-cpu
> stuff seems the one most likely to break, given that there was quite a
> lot of churn in that department recently.

Would it make sense to stick some printk's on the 'return 1' cases

>         /*
>          * static variable?
>          */
>         if ((addr >= start) && (addr < end))
>                 return 1;
> 
>         if (arch_is_kernel_data(addr))
>                 return 1;
> 
> #ifdef CONFIG_SMP
>         /*
>          * percpu var?
>          */
>         for_each_possible_cpu(i) {
>                 start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
>                 end   = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
>                                         + per_cpu_offset(i);
> 
>                 if ((addr >= start) && (addr < end))
>                         return 1;

or am I setting myself up for printk spam from hell if I do that?

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