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From: Tushar Behera <tushar.behera@linaro.org>
To: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-omap@vger.kernel.org, archit@ti.com, patches@linaro.org
Subject: Re: [PATCH] OMAPDSS: OMAPFB: Fix possible null pointer dereferencing
Date: Mon, 19 Nov 2012 15:11:55 +0530	[thread overview]
Message-ID: <50A9FEE3.70002@linaro.org> (raw)
In-Reply-To: <50A9F151.3010607@ti.com>

On 11/19/2012 02:14 PM, Tomi Valkeinen wrote:
> On 2012-11-19 07:10, Tushar Behera wrote:
>> If display is NULL, display->output would lead to kernel panic.
>>
>> Signed-off-by: Tushar Behera <tushar.behera@linaro.org>
>> ---
>>  drivers/video/omap2/omapfb/omapfb-ioctl.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/video/omap2/omapfb/omapfb-ioctl.c b/drivers/video/omap2/omapfb/omapfb-ioctl.c
>> index 55a39be..532a31b 100644
>> --- a/drivers/video/omap2/omapfb/omapfb-ioctl.c
>> +++ b/drivers/video/omap2/omapfb/omapfb-ioctl.c
>> @@ -787,7 +787,7 @@ int omapfb_ioctl(struct fb_info *fbi, unsigned int cmd, unsigned long arg)
>>  
>>  	case OMAPFB_WAITFORVSYNC:
>>  		DBG("ioctl WAITFORVSYNC\n");
>> -		if (!display && !display->output && !display->output->manager) {
>> +		if (!display || !display->output || !display->output->manager) {
>>  			r = -EINVAL;
>>  			break;
>>  		}
>>
> 
> Thanks, good catch. However, the patch description is not very good.

I agree.

> If you agree with the change, I'll apply the patch with the description:
> 

Please go ahead with the description that you have written here.

> 
> OMAPFB: Fix possible null pointer dereferencing                          
>                                                                          
> Commit 952cbaaa9b8beacc425f9aedf370468cbb737a2c (OMAPFB: Change          
> dssdev->manager references) added checks for OMAPFB_WAITFORVSYNC ioctl   
> to verify that the display, output and overlay manager exist. However,   
> the code erroneously uses && for each part, which means that             
> OMAPFB_WAITFORVSYNC may crash the kernel if no display, output or        
> manager is associated with the framebuffer.                              
>                                                                          
> This patch fixes the issue by using ||.                                  
> 
> 
>  Tomi
> 
> 

Thanks.

-- 
Tushar Behera

      reply	other threads:[~2012-11-19  9:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-19  5:10 [PATCH] OMAPDSS: OMAPFB: Fix possible null pointer dereferencing Tushar Behera
2012-11-19  8:44 ` Tomi Valkeinen
2012-11-19  9:41   ` Tushar Behera [this message]

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