[PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[Hamza Mahfooz]

Address the following error:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function ‘dc_stream_remove_writeback’:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: error: array subscript [0, 0] is outside array bounds of ‘struct dc_writeback_info[1]’ [-Werror=array-bounds]
  527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
      |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~
In file included from ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc.h:1269,
                 from ./drivers/gpu/drm/amd/amdgpu/../display/dc/inc/core_types.h:29,
                 from ./drivers/gpu/drm/amd/amdgpu/../display/dc/basics/dc_common.h:29,
                 from drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:27:
./drivers/gpu/drm/amd/amdgpu/../display/dc/dc_stream.h:241:34: note: while referencing ‘writeback_info’
  241 |         struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
      |

Currently, we aren't checking to see if j remains within
writeback_info[]'s bounds. So, add a check to make sure that we aren't
overflowing the buffer.

Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
index 3ca1592ce7ac..ae13887756bf 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
@@ -520,7 +520,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
 	}
 
 	/* remove writeback info for disabled writeback pipes from stream */
-	for (i = 0, j = 0; i < stream->num_wb_info; i++) {
+	for (i = 0, j = 0; i < stream->num_wb_info && j < MAX_DWB_PIPES; i++) {
 		if (stream->writeback_info[i].wb_enabled) {
 			if (i != j)
 				/* trim the array */
-- 
2.37.2

Re: [PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[Pillai, Aurabindo]

[-- Attachment #1: Type: text/plain, Size: 3290 bytes --]

[AMD Official Use Only - General]

Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>

--

Regards,
Jay
________________________________
From: Mahfooz, Hamza <Hamza.Mahfooz@amd.com>
Sent: Tuesday, September 27, 2022 3:12 PM
To: linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>
Cc: Mahfooz, Hamza <Hamza.Mahfooz@amd.com>; Wentland, Harry <Harry.Wentland@amd.com>; Li, Sun peng (Leo) <Sunpeng.Li@amd.com>; Siqueira, Rodrigo <Rodrigo.Siqueira@amd.com>; Deucher, Alexander <Alexander.Deucher@amd.com>; Koenig, Christian <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Lee, Alvin <Alvin.Lee2@amd.com>; Hung, Alex <Alex.Hung@amd.com>; Kotarac, Pavle <Pavle.Kotarac@amd.com>; Wang, Chao-kai (Stylon) <Stylon.Wang@amd.com>; Pillai, Aurabindo <Aurabindo.Pillai@amd.com>; Ma, Leo <Hanghong.Ma@amd.com>; Wu, Hersen <hersenxs.wu@amd.com>; Po-Yu Hsieh Paul <Paul.Hsieh@amd.com>; Jimmy Kizito <Jimmy.Kizito@amd.com>; amd-gfx@lists.freedesktop.org <amd-gfx@lists.freedesktop.org>; dri-devel@lists.freedesktop.org <dri-devel@lists.freedesktop.org>
Subject: [PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

Address the following error:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function ‘dc_stream_remove_writeback’:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: error: array subscript [0, 0] is outside array bounds of ‘struct dc_writeback_info[1]’ [-Werror=array-bounds]
  527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
      |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~
In file included from ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc.h:1269,
                 from ./drivers/gpu/drm/amd/amdgpu/../display/dc/inc/core_types.h:29,
                 from ./drivers/gpu/drm/amd/amdgpu/../display/dc/basics/dc_common.h:29,
                 from drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:27:
./drivers/gpu/drm/amd/amdgpu/../display/dc/dc_stream.h:241:34: note: while referencing ‘writeback_info’
  241 |         struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
      |

Currently, we aren't checking to see if j remains within
writeback_info[]'s bounds. So, add a check to make sure that we aren't
overflowing the buffer.

Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
index 3ca1592ce7ac..ae13887756bf 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
@@ -520,7 +520,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
         }

         /* remove writeback info for disabled writeback pipes from stream */
-       for (i = 0, j = 0; i < stream->num_wb_info; i++) {
+       for (i = 0, j = 0; i < stream->num_wb_info && j < MAX_DWB_PIPES; i++) {
                 if (stream->writeback_info[i].wb_enabled) {
                         if (i != j)
                                 /* trim the array */
--
2.37.2


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Re: [PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[Felix Kuehling]

I'm still seeing a warning even with this fix:

/home/fkuehlin/compute/kernel/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function ?dc_stream_remove_writeback?:
/home/fkuehlin/compute/kernel/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: warning: array subscript 1 is above array bounds of ?struct dc_writeback_info[1]? [-Warray-bounds]
   527 |     stream->writeback_info[j] = stream->writeback_info[i];
       |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~

Regards,
   Felix


Am 2022-09-27 um 16:35 schrieb Pillai, Aurabindo:
>
> [AMD Official Use Only - General]
>
>
> [AMD Official Use Only - General]
>
>
> Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
>
> --
>
> Regards,
> Jay
> ------------------------------------------------------------------------
> *From:* Mahfooz, Hamza <Hamza.Mahfooz@amd.com>
> *Sent:* Tuesday, September 27, 2022 3:12 PM
> *To:* linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>
> *Cc:* Mahfooz, Hamza <Hamza.Mahfooz@amd.com>; Wentland, Harry 
> <Harry.Wentland@amd.com>; Li, Sun peng (Leo) <Sunpeng.Li@amd.com>; 
> Siqueira, Rodrigo <Rodrigo.Siqueira@amd.com>; Deucher, Alexander 
> <Alexander.Deucher@amd.com>; Koenig, Christian 
> <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David 
> Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Lee, Alvin 
> <Alvin.Lee2@amd.com>; Hung, Alex <Alex.Hung@amd.com>; Kotarac, Pavle 
> <Pavle.Kotarac@amd.com>; Wang, Chao-kai (Stylon) 
> <Stylon.Wang@amd.com>; Pillai, Aurabindo <Aurabindo.Pillai@amd.com>; 
> Ma, Leo <Hanghong.Ma@amd.com>; Wu, Hersen <hersenxs.wu@amd.com>; Po-Yu 
> Hsieh Paul <Paul.Hsieh@amd.com>; Jimmy Kizito <Jimmy.Kizito@amd.com>; 
> amd-gfx@lists.freedesktop.org <amd-gfx@lists.freedesktop.org>; 
> dri-devel@lists.freedesktop.org <dri-devel@lists.freedesktop.org>
> *Subject:* [PATCH] drm/amd/display: fix array-bounds error in 
> dc_stream_remove_writeback()
> Address the following error:
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 
> ‘dc_stream_remove_writeback’:
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: 
> error: array subscript [0, 0] is outside array bounds of ‘struct 
> dc_writeback_info[1]’ [-Werror=array-bounds]
>   527 | stream->writeback_info[j] = stream->writeback_info[i];
>       | ~~~~~~~~~~~~~~~~~~~~~~^~~
> In file included from 
> ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc.h:1269,
>                  from 
> ./drivers/gpu/drm/amd/amdgpu/../display/dc/inc/core_types.h:29,
>                  from 
> ./drivers/gpu/drm/amd/amdgpu/../display/dc/basics/dc_common.h:29,
>                  from 
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:27:
> ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc_stream.h:241:34: note: 
> while referencing ‘writeback_info’
>   241 |         struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
>       |
>
> Currently, we aren't checking to see if j remains within
> writeback_info[]'s bounds. So, add a check to make sure that we aren't
> overflowing the buffer.
>
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
> ---
>  drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c 
> b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
> index 3ca1592ce7ac..ae13887756bf 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
> @@ -520,7 +520,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
>          }
>
>          /* remove writeback info for disabled writeback pipes from 
> stream */
> -       for (i = 0, j = 0; i < stream->num_wb_info; i++) {
> +       for (i = 0, j = 0; i < stream->num_wb_info && j < 
> MAX_DWB_PIPES; i++) {
>                  if (stream->writeback_info[i].wb_enabled) {
>                          if (i != j)
>                                  /* trim the array */
> -- 
> 2.37.2
>

Re: [PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[Hamza Mahfooz]

On 2022-09-29 11:36, Felix Kuehling wrote:
> I'm still seeing a warning even with this fix:
> 
> /home/fkuehlin/compute/kernel/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function ?dc_stream_remove_writeback?:
> /home/fkuehlin/compute/kernel/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: warning: array subscript 1 is above array bounds of ?struct dc_writeback_info[1]? [-Warray-bounds]
>    527 |     stream->writeback_info[j] = stream->writeback_info[i];
>        |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~
> 

What version of GCC are you using? I don't see it on GCC 12.2 with this 
patch applied.

> Regards,
>    Felix
> 
> 
> Am 2022-09-27 um 16:35 schrieb Pillai, Aurabindo:
>>
>> [AMD Official Use Only - General]
>>
>>
>> [AMD Official Use Only - General]
>>
>>
>> Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
>>
>> -- 
>>
>> Regards,
>> Jay
>> ------------------------------------------------------------------------
>> *From:* Mahfooz, Hamza <Hamza.Mahfooz@amd.com>
>> *Sent:* Tuesday, September 27, 2022 3:12 PM
>> *To:* linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>
>> *Cc:* Mahfooz, Hamza <Hamza.Mahfooz@amd.com>; Wentland, Harry 
>> <Harry.Wentland@amd.com>; Li, Sun peng (Leo) <Sunpeng.Li@amd.com>; 
>> Siqueira, Rodrigo <Rodrigo.Siqueira@amd.com>; Deucher, Alexander 
>> <Alexander.Deucher@amd.com>; Koenig, Christian 
>> <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David 
>> Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Lee, Alvin 
>> <Alvin.Lee2@amd.com>; Hung, Alex <Alex.Hung@amd.com>; Kotarac, Pavle 
>> <Pavle.Kotarac@amd.com>; Wang, Chao-kai (Stylon) 
>> <Stylon.Wang@amd.com>; Pillai, Aurabindo <Aurabindo.Pillai@amd.com>; 
>> Ma, Leo <Hanghong.Ma@amd.com>; Wu, Hersen <hersenxs.wu@amd.com>; Po-Yu 
>> Hsieh Paul <Paul.Hsieh@amd.com>; Jimmy Kizito <Jimmy.Kizito@amd.com>; 
>> amd-gfx@lists.freedesktop.org <amd-gfx@lists.freedesktop.org>; 
>> dri-devel@lists.freedesktop.org <dri-devel@lists.freedesktop.org>
>> *Subject:* [PATCH] drm/amd/display: fix array-bounds error in 
>> dc_stream_remove_writeback()
>> Address the following error:
>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 
>> ‘dc_stream_remove_writeback’:
>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: 
>> error: array subscript [0, 0] is outside array bounds of ‘struct 
>> dc_writeback_info[1]’ [-Werror=array-bounds]
>>   527 | stream->writeback_info[j] = stream->writeback_info[i];
>>       | ~~~~~~~~~~~~~~~~~~~~~~^~~
>> In file included from 
>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc.h:1269,
>>                  from 
>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/inc/core_types.h:29,
>>                  from 
>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/basics/dc_common.h:29,
>>                  from 
>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:27:
>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc_stream.h:241:34: note: 
>> while referencing ‘writeback_info’
>>   241 |         struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
>>       |
>>
>> Currently, we aren't checking to see if j remains within
>> writeback_info[]'s bounds. So, add a check to make sure that we aren't
>> overflowing the buffer.
>>
>> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
>> ---
>>  drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c 
>> b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
>> index 3ca1592ce7ac..ae13887756bf 100644
>> --- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
>> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
>> @@ -520,7 +520,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
>>          }
>>
>>          /* remove writeback info for disabled writeback pipes from 
>> stream */
>> -       for (i = 0, j = 0; i < stream->num_wb_info; i++) {
>> +       for (i = 0, j = 0; i < stream->num_wb_info && j < 
>> MAX_DWB_PIPES; i++) {
>>                  if (stream->writeback_info[i].wb_enabled) {
>>                          if (i != j)
>>                                  /* trim the array */
>> -- 
>> 2.37.2
>>

-- 
Hamza

Re: [PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[Felix Kuehling]

Am 2022-09-29 um 11:41 schrieb Hamza Mahfooz:
>
>
> On 2022-09-29 11:36, Felix Kuehling wrote:
>> I'm still seeing a warning even with this fix:
>>
>> /home/fkuehlin/compute/kernel/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: 
>> In function ?dc_stream_remove_writeback?:
>> /home/fkuehlin/compute/kernel/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: 
>> warning: array subscript 1 is above array bounds of ?struct 
>> dc_writeback_info[1]? [-Warray-bounds]
>>    527 |     stream->writeback_info[j] = stream->writeback_info[i];
>>        | ~~~~~~~~~~~~~~~~~~~~~~^~~
>>
>
> What version of GCC are you using? I don't see it on GCC 12.2 with 
> this patch applied.

gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0

Regards,
   Felix


>
>> Regards,
>>    Felix
>>
>>
>> Am 2022-09-27 um 16:35 schrieb Pillai, Aurabindo:
>>>
>>> [AMD Official Use Only - General]
>>>
>>>
>>> [AMD Official Use Only - General]
>>>
>>>
>>> Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
>>>
>>> -- 
>>>
>>> Regards,
>>> Jay
>>> ------------------------------------------------------------------------ 
>>>
>>> *From:* Mahfooz, Hamza <Hamza.Mahfooz@amd.com>
>>> *Sent:* Tuesday, September 27, 2022 3:12 PM
>>> *To:* linux-kernel@vger.kernel.org <linux-kernel@vger.kernel.org>
>>> *Cc:* Mahfooz, Hamza <Hamza.Mahfooz@amd.com>; Wentland, Harry 
>>> <Harry.Wentland@amd.com>; Li, Sun peng (Leo) <Sunpeng.Li@amd.com>; 
>>> Siqueira, Rodrigo <Rodrigo.Siqueira@amd.com>; Deucher, Alexander 
>>> <Alexander.Deucher@amd.com>; Koenig, Christian 
>>> <Christian.Koenig@amd.com>; Pan, Xinhui <Xinhui.Pan@amd.com>; David 
>>> Airlie <airlied@linux.ie>; Daniel Vetter <daniel@ffwll.ch>; Lee, 
>>> Alvin <Alvin.Lee2@amd.com>; Hung, Alex <Alex.Hung@amd.com>; Kotarac, 
>>> Pavle <Pavle.Kotarac@amd.com>; Wang, Chao-kai (Stylon) 
>>> <Stylon.Wang@amd.com>; Pillai, Aurabindo <Aurabindo.Pillai@amd.com>; 
>>> Ma, Leo <Hanghong.Ma@amd.com>; Wu, Hersen <hersenxs.wu@amd.com>; 
>>> Po-Yu Hsieh Paul <Paul.Hsieh@amd.com>; Jimmy Kizito 
>>> <Jimmy.Kizito@amd.com>; amd-gfx@lists.freedesktop.org 
>>> <amd-gfx@lists.freedesktop.org>; dri-devel@lists.freedesktop.org 
>>> <dri-devel@lists.freedesktop.org>
>>> *Subject:* [PATCH] drm/amd/display: fix array-bounds error in 
>>> dc_stream_remove_writeback()
>>> Address the following error:
>>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In 
>>> function ‘dc_stream_remove_writeback’:
>>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: 
>>> error: array subscript [0, 0] is outside array bounds of ‘struct 
>>> dc_writeback_info[1]’ [-Werror=array-bounds]
>>>   527 | stream->writeback_info[j] = stream->writeback_info[i];
>>>       | ~~~~~~~~~~~~~~~~~~~~~~^~~
>>> In file included from 
>>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc.h:1269,
>>>                  from 
>>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/inc/core_types.h:29,
>>>                  from 
>>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/basics/dc_common.h:29,
>>>                  from 
>>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:27:
>>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc_stream.h:241:34: note: 
>>> while referencing ‘writeback_info’
>>>   241 |         struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
>>>       |
>>>
>>> Currently, we aren't checking to see if j remains within
>>> writeback_info[]'s bounds. So, add a check to make sure that we aren't
>>> overflowing the buffer.
>>>
>>> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
>>> ---
>>>  drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c 
>>> b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
>>> index 3ca1592ce7ac..ae13887756bf 100644
>>> --- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
>>> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c
>>> @@ -520,7 +520,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
>>>          }
>>>
>>>          /* remove writeback info for disabled writeback pipes from 
>>> stream */
>>> -       for (i = 0, j = 0; i < stream->num_wb_info; i++) {
>>> +       for (i = 0, j = 0; i < stream->num_wb_info && j < 
>>> MAX_DWB_PIPES; i++) {
>>>                  if (stream->writeback_info[i].wb_enabled) {
>>>                          if (i != j)
>>>                                  /* trim the array */
>>> -- 
>>> 2.37.2
>>>
>

Re: [PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[Guenter Roeck]

On Tue, Sep 27, 2022 at 03:12:00PM -0400, Hamza Mahfooz wrote:
> Address the following error:
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function ‘dc_stream_remove_writeback’:
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: error: array subscript [0, 0] is outside array bounds of ‘struct dc_writeback_info[1]’ [-Werror=array-bounds]
>   527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
>       |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~
> In file included from ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc.h:1269,
>                  from ./drivers/gpu/drm/amd/amdgpu/../display/dc/inc/core_types.h:29,
>                  from ./drivers/gpu/drm/amd/amdgpu/../display/dc/basics/dc_common.h:29,
>                  from drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:27:
> ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc_stream.h:241:34: note: while referencing ‘writeback_info’
>   241 |         struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
>       |
> 
> Currently, we aren't checking to see if j remains within
> writeback_info[]'s bounds. So, add a check to make sure that we aren't
> overflowing the buffer.
> 
> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>

With gcc 11.3, this patch doesn't fix a problem, it introduces one.

Building csky:allmodconfig ... failed
--------------
Error log:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:83: error: array subscript 1 is above array bounds of 'struct dc_writeback_info[1]' [-Werror=array-bounds]
  527 |                                 stream->writeback_info[j] = stream->writeback_info[i];

Building mips:allmodconfig ... failed
--------------
Error log:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:83: error: array subscript [0, 0] is outside array bounds of 'struct dc_writeback_info[1]' [-Werror=array-bounds]
  527 |                                 stream->writeback_info[j] = stream->writeback_info[i];

Building arm:allmodconfig ... failed
--------------
Error log:
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:83: error: array subscript [0, 0] is outside array bounds of 'struct dc_writeback_info[1]' [-Werror=array-bounds]
  527 |                                 stream->writeback_info[j] = stream->writeback_info[i];

Guenter

Re: [PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[Guenter Roeck]

On Wed, Oct 05, 2022 at 11:46:15PM -0700, Guenter Roeck wrote:
> On Tue, Sep 27, 2022 at 03:12:00PM -0400, Hamza Mahfooz wrote:
> > Address the following error:
> > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function ‘dc_stream_remove_writeback’:
> > drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: error: array subscript [0, 0] is outside array bounds of ‘struct dc_writeback_info[1]’ [-Werror=array-bounds]
> >   527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
> >       |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~
> > In file included from ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc.h:1269,
> >                  from ./drivers/gpu/drm/amd/amdgpu/../display/dc/inc/core_types.h:29,
> >                  from ./drivers/gpu/drm/amd/amdgpu/../display/dc/basics/dc_common.h:29,
> >                  from drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:27:
> > ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc_stream.h:241:34: note: while referencing ‘writeback_info’
> >   241 |         struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
> >       |
> > 
> > Currently, we aren't checking to see if j remains within
> > writeback_info[]'s bounds. So, add a check to make sure that we aren't
> > overflowing the buffer.
> > 
> > Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
> 
> With gcc 11.3, this patch doesn't fix a problem, it introduces one.
> 
> Building csky:allmodconfig ... failed
> --------------
> Error log:
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:83: error: array subscript 1 is above array bounds of 'struct dc_writeback_info[1]' [-Werror=array-bounds]
>   527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
> 
> Building mips:allmodconfig ... failed
> --------------
> Error log:
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:83: error: array subscript [0, 0] is outside array bounds of 'struct dc_writeback_info[1]' [-Werror=array-bounds]
>   527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
> 
> Building arm:allmodconfig ... failed
> --------------
> Error log:
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:83: error: array subscript [0, 0] is outside array bounds of 'struct dc_writeback_info[1]' [-Werror=array-bounds]
>   527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
> 

#regzbot introduced: 5d8c3e836fc2

Complete list of build failures in my test system due to this patch,
observed when building with gcc 11.3:

Build results:
	total: 149 pass: 131 fail: 18
Failed builds:
	alpha:allmodconfig
	arm:allmodconfig
	arm64:allmodconfig
	csky:allmodconfig
	i386:allyesconfig
	i386:allmodconfig
	mips:allmodconfig
	openrisc:allmodconfig
	parisc:allmodconfig
	powerpc:allmodconfig
	powerpc:ppc32_allmodconfig
	riscv32:allmodconfig
	riscv:allmodconfig
	s390:allmodconfig
	sparc64:allmodconfig
	x86_64:allyesconfig
	x86_64:allmodconfig
	xtensa:allmodconfig

Guenter

Re: [PATCH] drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()

[Thorsten Leemhuis]

[removed a lot of people from the list of recipients, as this is mainly
for Guenter]

Hi Guenter!

On 06.10.22 19:23, Guenter Roeck wrote:
> On Wed, Oct 05, 2022 at 11:46:15PM -0700, Guenter Roeck wrote:
>> On Tue, Sep 27, 2022 at 03:12:00PM -0400, Hamza Mahfooz wrote:
>>> Address the following error:
>>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function ‘dc_stream_remove_writeback’:
>>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:55: error: array subscript [0, 0] is outside array bounds of ‘struct dc_writeback_info[1]’ [-Werror=array-bounds]
>>>   527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
>>>       |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~
>>> In file included from ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc.h:1269,
>>>                  from ./drivers/gpu/drm/amd/amdgpu/../display/dc/inc/core_types.h:29,
>>>                  from ./drivers/gpu/drm/amd/amdgpu/../display/dc/basics/dc_common.h:29,
>>>                  from drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:27:
>>> ./drivers/gpu/drm/amd/amdgpu/../display/dc/dc_stream.h:241:34: note: while referencing ‘writeback_info’
>>>   241 |         struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
>>>       |
>>>
>>> Currently, we aren't checking to see if j remains within
>>> writeback_info[]'s bounds. So, add a check to make sure that we aren't
>>> overflowing the buffer.
>>>
>>> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
>>
>> With gcc 11.3, this patch doesn't fix a problem, it introduces one.
>>
>> Building csky:allmodconfig ... failed
>> --------------
>> Error log:
>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
>> drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:527:83: error: array subscript 1 is above array bounds of 'struct dc_writeback_info[1]' [-Werror=array-bounds]
>>   527 |                                 stream->writeback_info[j] = stream->writeback_info[i];
>
> [...]
>
> #regzbot introduced: 5d8c3e836fc2

Thx for using regzbot, much appreciated. JFYI, the initial report was
your own mail you were replying to here, so a "#regzbot ^introduced:
..."  would have been more appropriate. In this case it didn't matter
anyway, as the fix didn't include a "Link:" tag to the initial report
anyway. No worries, I just have to tell regzbot about the fix manually then:

#regzbot fixed-by: faf4d8e07f5b67

Ciao, Thorsten