linux-kernel - Re: [PATCH v2 1/3] dell-wmi: Stop storing pointers to DMI tables

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Message-ID: <20160119094145.599d1b6c@endymion.delvare>
Date:	Tue, 19 Jan 2016 09:41:45 +0100
From:	Jean Delvare <jdelvare@...e.de>
To:	Andy Lutomirski <luto@...nel.org>
Cc:	Pali Rohár <pali.rohar@...il.com>,
	platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/3] dell-wmi: Stop storing pointers to DMI tables

Hi Andy,

On Mon, 18 Jan 2016 12:59:38 -0800, Andy Lutomirski wrote:
> The dmi_walk function maps the DMI table, walks it, and unmaps it.
> This means that the dell_bios_hotkey_table that find_hk_type stores
> points to unmapped memory by the time it gets read.
> 
> I've been able to trigger crashes caused by the stale pointer a
> couple of times, but never on a stock kernel.
> 
> Fix it by generating the keymap in the dmi_walk callback instead of
> storing a pointer.
> 
> Signed-off-by: Andy Lutomirski <luto@...nel.org>
> ---
> 
> Notes:
>     Changes from v1:
>      - Rename handle_dmi_table to handle_dmi_entry (Jean)
>      - Remove useless assignment to results->err (Jean)
> 
>  drivers/platform/x86/dell-wmi.c | 68 +++++++++++++++++++++++++----------------
>  1 file changed, 41 insertions(+), 27 deletions(-)
> (...)
> @@ -431,7 +446,6 @@ static int __init dell_wmi_init(void)
>  		return -ENODEV;
>  	}
>  
> -	dmi_walk(find_hk_type, NULL);
>  

Please also delete the following blank line, to avoid two consecutive
blank lines.

>  	err = dell_wmi_input_setup();
>  	if (err)

Other than this, it looks good to me, so after fixing the above, you
can add:

Reviewed-by: Jean Delvare <jdelvare@...e.de>

-- 
Jean Delvare
SUSE L3 Support