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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: Re: [Bug 202149] New: NULL Pointer Dereference in __split_huge_pmd on PPC64LE
In-Reply-To: <20190104170459.c8c7fa57ba9bc8a69dee5666@linux-foundation.org>
References: <bug-202149-27@https.bugzilla.kernel.org/> <20190104170459.c8c7fa57ba9bc8a69dee5666@linux-foundation.org>
Date: Tue, 08 Jan 2019 12:45:08 +0530
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To: Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org
Cc: bugzilla-daemon@bugzilla.kernel.org, kernel@bluematt.me

Andrew Morton <akpm@linux-foundation.org> writes:

> (switched to email.  Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
>
> On Fri, 04 Jan 2019 22:49:52 +0000 bugzilla-daemon@bugzilla.kernel.org wrote:
>
>> https://bugzilla.kernel.org/show_bug.cgi?id=202149
>> 
>>             Bug ID: 202149
>>            Summary: NULL Pointer Dereference in __split_huge_pmd on
>>                     PPC64LE
>
> I think that trace is pointing at the ppc-specific
> pgtable_trans_huge_withdraw()?
>

That is correct. 

Matt,
Can you share the .config used for the kernel. Does this happen only
with 4K page size ?

-aneesh