linux-kernel - Re: [PATCH v2 2/2] sparc64: Fix pagetable freeing for hugepage regions

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Message-Id: <20160728.210048.165773321219658930.davem@davemloft.net>
Date:	Thu, 28 Jul 2016 21:00:48 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	nitin.m.gupta@...cle.com
Cc:	akpm@...ux-foundation.org, dingel@...ux.vnet.ibm.com,
	schwidefsky@...ibm.com, kirill.shutemov@...ux.intel.com,
	sparclinux@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] sparc64: Fix pagetable freeing for hugepage
 regions

From: Nitin Gupta <nitin.m.gupta@...cle.com>
Date: Thu, 23 Jun 2016 15:05:36 -0700

> 8M pages now allocate page tables till PMD level only.
> So, when freeing page table for 8M hugepage backed region,
> make sure we don't try to access non-existent PTE level.
> 
> Signed-off-by: Nitin Gupta <nitin.m.gupta@...cle.com>

The manner in which you have submitted this change breaks
bisectability.

The "problem" you are fixing here is introduced by you in patch #1.

You need to combine these two changes together, otherwise there is
an intermediate state where the kernel is broken by your changes.