[PATCH] ARM: OMAP2: possible division by 0

[PATCH] ARM: OMAP2: possible division by 0

[Roel Kluin]

In linus' git tree the functions can be found at:
vi arch/arm/mach-omap2/usb-tusb6010.c +200	- tusb6010_platform_retime()
vi arch/arm/mach-omap2/gpmc.c +94		- gpmc_get_fclk_period()
vi arch/arm/mach-omap2/usb-tusb6010.c +53	- tusb_set_async_mode()
vi arch/arm/mach-omap2/usb-tusb6010.c +111	- tusb_set_sync_mode()

is -ENODEV appropriate when sysclk_ps == 0?

This was found by code analysis, please review.
------------------------------>8-------------8<---------------------------------
gpmc_get_fclk_period() may return 0 when gpmc_l3_clk is not enabled. This is
not checked in tusb6010_platform_retime() nor in tusb_set_async_mode() it
seems. In tusb_set_sync_mode() this may result in a division by zero.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
diff --git a/arch/arm/mach-omap2/usb-tusb6010.c b/arch/arm/mach-omap2/usb-tusb6010.c
index 15e5090..8df55f4 100644
--- a/arch/arm/mach-omap2/usb-tusb6010.c
+++ b/arch/arm/mach-omap2/usb-tusb6010.c
@@ -187,7 +187,7 @@ int tusb6010_platform_retime(unsigned is_refclk)
 	unsigned	sysclk_ps;
 	int		status;
 
-	if (!refclk_psec)
+	if (!refclk_psec || sysclk_ps == 0)
 		return -ENODEV;
 
 	sysclk_ps = is_refclk ? refclk_psec : TUSB6010_OSCCLK_60;

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[APPLIED] [PATCH] ARM: OMAP2: possible division by 0

[Tony Lindgren]

This patch has been applied to the linux-omap
by youw fwiendly patch wobot.

Commit: a170fc43065439cff6d18f02a1571a92718b9623

PatchWorks
http://patchwork.kernel.org/patch/12591/

Git
http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=commit;h=a170fc43065439cff6d18f02a1571a92718b9623

Re: [PATCH] ARM: OMAP2: possible division by 0

[Tony Lindgren]

* Roel Kluin <roel.kluin@gmail.com> [090317 04:50]:
> In linus' git tree the functions can be found at:
> vi arch/arm/mach-omap2/usb-tusb6010.c +200	- tusb6010_platform_retime()
> vi arch/arm/mach-omap2/gpmc.c +94		- gpmc_get_fclk_period()
> vi arch/arm/mach-omap2/usb-tusb6010.c +53	- tusb_set_async_mode()
> vi arch/arm/mach-omap2/usb-tusb6010.c +111	- tusb_set_sync_mode()
> 
> is -ENODEV appropriate when sysclk_ps == 0?
> 
> This was found by code analysis, please review.
> ------------------------------>8-------------8<---------------------------------
> gpmc_get_fclk_period() may return 0 when gpmc_l3_clk is not enabled. This is
> not checked in tusb6010_platform_retime() nor in tusb_set_async_mode() it
> seems. In tusb_set_sync_mode() this may result in a division by zero.
> 
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>

Looks like a valid fix to me. I'll add it to omap-fixes queue.
To me it sounds like there's no urgent need to get this integrated
as we're missing most of the omap2 PM still.

Tony

> ---
> diff --git a/arch/arm/mach-omap2/usb-tusb6010.c b/arch/arm/mach-omap2/usb-tusb6010.c
> index 15e5090..8df55f4 100644
> --- a/arch/arm/mach-omap2/usb-tusb6010.c
> +++ b/arch/arm/mach-omap2/usb-tusb6010.c
> @@ -187,7 +187,7 @@ int tusb6010_platform_retime(unsigned is_refclk)
>  	unsigned	sysclk_ps;
>  	int		status;
>  
> -	if (!refclk_psec)
> +	if (!refclk_psec || sysclk_ps == 0)
>  		return -ENODEV;
>  
>  	sysclk_ps = is_refclk ? refclk_psec : TUSB6010_OSCCLK_60;
> --
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