linux-kernel - Re: [PATCH] x86/mm: Give the correct initail value to the pmd

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Date:	Tue, 11 Nov 2014 19:36:08 +0800
From:	Minfei Huang <mhuang@...hat.com>
To:	Minfei Huang <mnfhuang@...il.com>
Cc:	tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
	hpa@...or.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/mm: Give the correct initail value to the pmd_idx

Could someone who help me review my patch?

Thanks
Minfei

On 11/06/14 at 01:41pm, Minfei Huang wrote:
> The variable value is undefined from the stack eara. So it makes sense to
> init the variable to run process correctly.
> 
> If the variable pmd_idx inits the value more than PTRS_PER_PMD, the
> count may be smaller than the correct value, and the allocated page may
> be not enough for pte entry.
> 
> The kernel may panic cause by the undefine variable which is allocated
> from stack.
> 
> Signed-off-by: Minfei Huang <mnfhuang@...il.com>
> ---
>  arch/x86/mm/init_32.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
> index c8140e1..c23ab1e 100644
> --- a/arch/x86/mm/init_32.c
> +++ b/arch/x86/mm/init_32.c
> @@ -137,6 +137,7 @@ page_table_range_init_count(unsigned long start, unsigned long end)
>  
>  	vaddr = start;
>  	pgd_idx = pgd_index(vaddr);
> +	pmd_idx = pmd_index(vaddr);
>  
>  	for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) {
>  		for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
> -- 
> 1.8.3.1
> 
> --
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