linux-kernel - Re: [PATCH v8 3/5] x86/KASLR: Give a warning if movable_node specified without kaslr

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Message-ID: <20180119034825.GE1753@localhost.localdomain>
Date:   Fri, 19 Jan 2018 11:48:25 +0800
From:   Baoquan He <bhe@...hat.com>
To:     Chao Fan <fanc.fnst@...fujitsu.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org, hpa@...or.com,
        tglx@...utronix.de, mingo@...hat.com, keescook@...omium.org,
        yasu.isimatu@...il.com, indou.takao@...fujitsu.com,
        lcapitulino@...hat.com
Subject: Re: [PATCH v8 3/5] x86/KASLR: Give a warning if movable_node
 specified without kaslr_mem=

On 01/19/18 at 11:31am, Chao Fan wrote:
> Since only 'movable_node' specified without 'kaslr_mem=' may break
> memory hotplug, so reconmmend users using 'kaslr_mem=' when
> 'movable_node' specified.
> 
> Signed-off-by: Chao Fan <fanc.fnst@...fujitsu.com>
> ---
>  arch/x86/boot/compressed/kaslr.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
> index b200a7ceafc1..8703cc764306 100644
> --- a/arch/x86/boot/compressed/kaslr.c
> +++ b/arch/x86/boot/compressed/kaslr.c
> @@ -282,6 +282,16 @@ static int handle_mem_filter(void)
>  	    !strstr(args, "kaslr_mem="))
>  		return 0;

Looks good to me.

Acked-by: Baoquan He <bhe@...hat.com>

>  
> +#ifdef CONFIG_MEMORY_HOTPLUG
> +	/*
> +	 * Check if 'kaslr_mem=' specified when 'movable_node' found. If not,
> +	 * just give warrning. Otherwise memory hotplug could be
> +	 * affected if kernel is put on movable memory regions.
> +	 */
> +	if (strstr(args, "movable_node") && !strstr(args, "kaslr_mem="))
> +		warn("'kaslr_mem=' should be specified when using 'movable_node'.\n");
> +#endif
> +
>  	tmp_cmdline = malloc(len + 1);
>  	if (!tmp_cmdline)
>  		error("Failed to allocate space for tmp_cmdline");
> -- 
> 2.14.3
> 
> 
>