linux-kernel - Re: [PATCH v2] platform/x86: thinkpad_acpi: Initialize local in_tablet

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Message-ID: <20161215124424.GA20905@khazad-dum.debian.net>
Date:   Thu, 15 Dec 2016 10:44:24 -0200
From:   Henrique de Moraes Holschuh <hmh@....eng.br>
To:     Darren Hart <dvhart@...ux.intel.com>
Cc:     Lyude <lyude@...hat.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-next@...r.kernel.org, linux-kernel@...r.kernel.org,
        platform-drivers-x86@...r.kernel.org
Subject: Re: [PATCH v2] platform/x86: thinkpad_acpi: Initialize local
 in_tablet_mode and type

On Wed, 14 Dec 2016, Darren Hart wrote:
> linux-next reported in_tablet_mode and type may be used uninitialized
> after:
> 
> b31800283868 ("platform/x86: thinkpad_acpi: Move tablet detection into separate function")
> 
> This turns out to be a false positive as the pr_info call cannot be
> reached if tp_features.hotkey_tablet (global scope) is 0, and
> in_tablet_mode and type are assigned in both places
> tp_features.hotkey_tablet is assigned.
> 
> Regardless, to make it explicit and avoid further reports, initialize
> in_tablet_mode to 0 and type to "".
> 
> Signed-off-by: Darren Hart <dvhart@...ux.intel.com>
> Cc: Lyude <lyude@...hat.com>
> Cc: Henrique de Moraes Holschuh <hmh@....eng.br>
> Cc: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

Acked-by: Henrique de Moraes Holschuh <hmh@....eng.br>

> ---
> Since v1: Initialize type also.
> 
>  drivers/platform/x86/thinkpad_acpi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index 69cb0da..c408390 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -3143,8 +3143,8 @@ typedef tpacpi_keymap_entry_t tpacpi_keymap_t[TPACPI_HOTKEY_MAP_LEN];
>  
>  static int hotkey_init_tablet_mode(void)
>  {
> -	int in_tablet_mode, res;
> -	char *type;
> +	int in_tablet_mode = 0, res;
> +	char *type = "";
>  
>  	if (acpi_evalf(hkey_handle, &res, "MHKG", "qd")) {
>  		/* For X41t, X60t, X61t Tablets... */
> -- 
> 2.9.3
> 
> 

-- 
  Henrique Holschuh

  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot