linux-kernel - Re: [PATCH v7u1 20/31] x86, kexec: replace ident_mapping_init and init_level4

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Date:	Fri, 4 Jan 2013 22:01:19 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jan Kiszka <jan.kiszka@....de>,
	Jason Wessel <jason.wessel@...driver.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7u1 20/31] x86, kexec: replace ident_mapping_init and
 init_level4_page

On Thu, Jan 03, 2013 at 04:48:40PM -0800, Yinghai Lu wrote:
>  static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
>  {
> +	struct x86_mapping_info info = {
> +		.alloc_pgt_page	= alloc_pgt_page,
> +		.context	= image,
> +		.pmd_flag	= __PAGE_KERNEL_LARGE_EXEC,
> +	};

This is leaving ->kernel_mapping uninitialized to contain a random,
previous stack value. I don't think we want that.

>  	unsigned long mstart, mend;
>  	pgd_t *level4p;
>  	int result;
>  	int i;
>  
>  	level4p = (pgd_t *)__va(start_pgtable);
> -	result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
> +	clear_page(level4p);
> +	result = kernel_ident_mapping_init(&info, level4p,
> +						0, max_pfn << PAGE_SHIFT);
>  	if (result)
>  		return result;
>  
> @@ -225,7 +115,8 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
>  		mstart = image->segment[i].mem;
>  		mend   = mstart + image->segment[i].memsz;
>  
> -		result = ident_mapping_init(image, level4p, mstart, mend);
> +		result = kernel_ident_mapping_init(&info,
> +						 level4p, mstart, mend);
>  
>  		if (result)
>  			return result;
> -- 
> 1.7.10.4
> 
> 

-- 
Regards/Gruss,
Boris.
--
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