Re: [PATCH v7 3/5] x86/KASLR: Give a warning if movable_node specified without kaslr_mem=

From: Baoquan He <bhe@redhat.com>
To: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com,
	tglx@linutronix.de, mingo@redhat.com, keescook@chromium.org,
	yasu.isimatu@gmail.com, indou.takao@jp.fujitsu.com,
	lcapitulino@redhat.com
Subject: Re: [PATCH v7 3/5] x86/KASLR: Give a warning if movable_node specified without kaslr_mem=
Date: Wed, 17 Jan 2018 22:02:48 +0800	[thread overview]
Message-ID: <20180117140248.GG2321@localhost.localdomain> (raw)
In-Reply-To: <20180117105351.12226-4-fanc.fnst@cn.fujitsu.com>

On 01/17/18 at 06:53pm, 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@cn.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..dca846b522fc 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;
>  
> +#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 put on movable memory regions.
> +	 */
> +	if (strstr(args, "movable_node") && !strstr(args, "kaslr_mem="))
> +		warn("kaslr_mem= should specified when using movable_node.\n");
		      'kaslr_mem='     ^be
> +#endif
> +
>  	tmp_cmdline = malloc(len + 1);
>  	if (!tmp_cmdline)
>  		error("Failed to allocate space for tmp_cmdline");
> -- 
> 2.14.3
> 
> 
>