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Date: Fri, 20 Mar 2015 17:34:44 -0700 (PDT)
From: David Rientjes <rientjes@google.com>
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To: David Ahern <david.ahern@oracle.com>
cc: Linus Torvalds <torvalds@linux-foundation.org>,
        linux-mm <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: 4.0.0-rc4: panic in free_block
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On Fri, 20 Mar 2015, David Ahern wrote:

> Here's another data point: If I disable NUMA I don't see the problem.
> Performance drops, but no NULL pointer splats which would have been panics.
> 
> The 128 cpu ldom with NUMA enabled shows the problem every single time I do a
> kernel compile (-j 128). With NUMA disabled I have done 3 allyesconfig
> compiles without hitting the problem. I'll put the compiles into a loop while
> I head out for dinner.
> 

It might be helpful to enable CONFIG_DEBUG_SLAB if you're reproducing it.