linux-kernel - Re: Fw: RCU boot debug patch

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Date:	Wed, 27 Jul 2011 19:56:10 -0400
From:	Kyle Moffett <kyle@...fetthome.net>
To:	kernelmail.jms@...il.com
Cc:	paulmck@...ux.vnet.ibm.com, RKK <kulkarni.ravi4@...il.com>,
	linux-kernel@...r.kernel.org, cmm@...ibm.com
Subject: Re: Fw: RCU boot debug patch

On Wed, Jul 27, 2011 at 17:47,  <kernelmail.jms@...il.com> wrote:
>>A debug patch to verify if there is RCU callbacks before the rcu scheduler is active
> So something gives me the impression we may have an answer somewhere in this dmesg for this... ;-)
>
> Here is my dmesg (the whole thing):
>
> function free_object_rcu
> [    0.166707] RCU scheduler is not active yet, Calling _call_rcu() with this function free_object_rcu
> [....thousands of lines snipped...]
> [    0.225223] RCU scheduler is not active yet, Calling _call_rcu() with this function free_object_rcu

Well this looks an awful lot like a smoking gun here...

I can only find one function called "free_object_rcu", and it seems to be a
static function in mm/kmemleak.c, and it certainly does this:
   call_rcu(&object->rcu, free_object_rcu);

So the next question for you would be:  Do all the messages go away if you
turn off the kmemleak config option?

Cheers,
Kyle Moffett
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