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* [PATCH][next] drm/mgag200: Fix uninitialized variable delta
@ 2021-08-17 16:32 Colin King
  2021-08-17 18:22 ` Thomas Zimmermann
  0 siblings, 1 reply; 3+ messages in thread
From: Colin King @ 2021-08-17 16:32 UTC (permalink / raw)
  To: Dave Airlie, Thomas Zimmermann, David Airlie, Daniel Vetter,
	Sam Ravnborg, dri-devel
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

The variable delta is not initialized and this will cause unexpected
behaviour with the comparison of tmpdelta < delta. Fix this by setting
it to 0xffffffff. This matches the behaviour as in the similar function
mgag200_pixpll_compute_g200se_04.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: 2545ac960364 ("drm/mgag200: Abstract pixel PLL via struct mgag200_pll")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/gpu/drm/mgag200/mgag200_pll.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/mgag200/mgag200_pll.c b/drivers/gpu/drm/mgag200/mgag200_pll.c
index 7c903cf19c0d..18f1a6dd019a 100644
--- a/drivers/gpu/drm/mgag200/mgag200_pll.c
+++ b/drivers/gpu/drm/mgag200/mgag200_pll.c
@@ -125,6 +125,7 @@ static int mgag200_pixpll_compute_g200se_00(struct mgag200_pll *pixpll, long clo
 
 	m = n = p = s = 0;
 	permitteddelta = clock * 5 / 1000;
+	delta = 0xffffffff;
 
 	for (testp = 8; testp > 0; testp /= 2) {
 		if (clock * testp > vcomax)
-- 
2.32.0


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH][next] drm/mgag200: Fix uninitialized variable delta
  2021-08-17 16:32 [PATCH][next] drm/mgag200: Fix uninitialized variable delta Colin King
@ 2021-08-17 18:22 ` Thomas Zimmermann
  2021-08-17 20:11   ` Colin Ian King
  0 siblings, 1 reply; 3+ messages in thread
From: Thomas Zimmermann @ 2021-08-17 18:22 UTC (permalink / raw)
  To: Colin King, Dave Airlie, David Airlie, Daniel Vetter,
	Sam Ravnborg, dri-devel
  Cc: kernel-janitors, linux-kernel


[-- Attachment #1.1: Type: text/plain, Size: 1674 bytes --]

Hi

Am 17.08.21 um 18:32 schrieb Colin King:
> From: Colin Ian King <colin.king@canonical.com>
> 
> The variable delta is not initialized and this will cause unexpected
> behaviour with the comparison of tmpdelta < delta. Fix this by setting
> it to 0xffffffff. This matches the behaviour as in the similar function
> mgag200_pixpll_compute_g200se_04.
> 
> Addresses-Coverity: ("Uninitialized scalar variable")
> Fixes: 2545ac960364 ("drm/mgag200: Abstract pixel PLL via struct mgag200_pll")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>

But the commit message needs Fixes etc. I just sent out a patch for this 
issue myself. I'd like to merge both patches' tags and commit the result 
under your name. (You were first.) Is that ok for you?

Best regards
Thomas

> ---
>   drivers/gpu/drm/mgag200/mgag200_pll.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/mgag200/mgag200_pll.c b/drivers/gpu/drm/mgag200/mgag200_pll.c
> index 7c903cf19c0d..18f1a6dd019a 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_pll.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_pll.c
> @@ -125,6 +125,7 @@ static int mgag200_pixpll_compute_g200se_00(struct mgag200_pll *pixpll, long clo
>   
>   	m = n = p = s = 0;
>   	permitteddelta = clock * 5 / 1000;
> +	delta = 0xffffffff;
>   
>   	for (testp = 8; testp > 0; testp /= 2) {
>   		if (clock * testp > vcomax)
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH][next] drm/mgag200: Fix uninitialized variable delta
  2021-08-17 18:22 ` Thomas Zimmermann
@ 2021-08-17 20:11   ` Colin Ian King
  0 siblings, 0 replies; 3+ messages in thread
From: Colin Ian King @ 2021-08-17 20:11 UTC (permalink / raw)
  To: Thomas Zimmermann, Dave Airlie, David Airlie, Daniel Vetter,
	Sam Ravnborg, dri-devel
  Cc: kernel-janitors, linux-kernel

On 17/08/2021 19:22, Thomas Zimmermann wrote:
> Hi
> 
> Am 17.08.21 um 18:32 schrieb Colin King:
>> From: Colin Ian King <colin.king@canonical.com>
>>
>> The variable delta is not initialized and this will cause unexpected
>> behaviour with the comparison of tmpdelta < delta. Fix this by setting
>> it to 0xffffffff. This matches the behaviour as in the similar function
>> mgag200_pixpll_compute_g200se_04.
>>
>> Addresses-Coverity: ("Uninitialized scalar variable")
>> Fixes: 2545ac960364 ("drm/mgag200: Abstract pixel PLL via struct
>> mgag200_pll")
>> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> 
> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
> 
> But the commit message needs Fixes etc. I just sent out a patch for this
> issue myself. I'd like to merge both patches' tags and commit the result
> under your name. (You were first.) Is that ok for you?

Sure. Go ahead, Thanks

Colin

> 
> Best regards
> Thomas
> 
>> ---
>>   drivers/gpu/drm/mgag200/mgag200_pll.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/gpu/drm/mgag200/mgag200_pll.c
>> b/drivers/gpu/drm/mgag200/mgag200_pll.c
>> index 7c903cf19c0d..18f1a6dd019a 100644
>> --- a/drivers/gpu/drm/mgag200/mgag200_pll.c
>> +++ b/drivers/gpu/drm/mgag200/mgag200_pll.c
>> @@ -125,6 +125,7 @@ static int mgag200_pixpll_compute_g200se_00(struct
>> mgag200_pll *pixpll, long clo
>>         m = n = p = s = 0;
>>       permitteddelta = clock * 5 / 1000;
>> +    delta = 0xffffffff;
>>         for (testp = 8; testp > 0; testp /= 2) {
>>           if (clock * testp > vcomax)
>>
> 


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-08-17 20:12 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-17 16:32 [PATCH][next] drm/mgag200: Fix uninitialized variable delta Colin King
2021-08-17 18:22 ` Thomas Zimmermann
2021-08-17 20:11   ` Colin Ian King

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