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Date: Mon, 24 Feb 2003 14:33:41 -0800
From: Andrew Morton <akpm@digeo.com>
To: Paul Larson <plars@linuxtestproject.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] pte_alloc_kernel needs additional check
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Paul Larson <plars@linuxtestproject.org> wrote:
>
> This applies against 2.5.63.
> pte_alloc_kernel needs a check for pmd_present(*pmd) at the end.
> 
> Thanks,
> Paul Larson
> 
> --- linux-2.5.63/mm/memory.c	Mon Feb 24 13:05:31 2003
> +++ linux-2.5.63-fix/mm/memory.c	Mon Feb 24 15:45:05 2003
> @@ -186,7 +186,9 @@
>  		pmd_populate_kernel(mm, pmd, new);
>  	}
>  out:
> -	return pte_offset_kernel(pmd, address);
> +	if (pmd_present(*pmd))
> +		return pte_offset_kernel(pmd, address);
> +	return NULL;
>  }
>  #define PTE_TABLE_MASK	((PTRS_PER_PTE-1) * sizeof(pte_t))
>  #define PMD_TABLE_MASK	((PTRS_PER_PMD-1) * sizeof(pmd_t))

Confused.  I cannot see a codepath which makes this test necessary?


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