linux-next: build failure after merge of the drm tree

DISCUSSION [email protected] 5 participants 12 messages Sep 30, 2022 – Oct 6, 2022

Subsystems (4)

DRM drivers Linux-next tree Radeon and amdgpu DRM drivers AMD display core

lore

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lore

[email protected]

author maintainer

2022-09-30 11:15 UTC #0 lore raw

Hi all,

After merging the drm tree, today's linux-next build (x86_64 allmodconfig) failed like this:

/tmp/next/build/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
/tmp/next/build/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];
      |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~

cc1: all warnings being treated as errors

Caused by

5d8c3e836fc224 ("drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()")

I have reverted that commit for today.

Stephen Rothwell

2022-10-04 02:20 UTC #1 lore raw

Hi [email protected],

Quoted 8 lines · On Fri, 30 Sep 2022 11:54:34 +0100 [email protected] wrote:

After merging the drm tree, today's linux-next build (x86_64 allmodconfig) failed like this:
/tmp/next/build/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
/tmp/next/build/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];
      |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~

Quoted 7 lines

cc1: all warnings being treated as errors
Caused by
5d8c3e836fc224 ("drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()")
I have reverted that commit for today.

I am still getting this failure. The full error is:

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];
      |                                                             ~~~~~~~~~~~~~~~~~~~~~~^~~
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];
      |                                  ^~~~~~~~~~~~~~

I have reverted that commit again today.

Signature · 2 lines

Cheers,
Stephen Rothwell

David Airlie

2022-10-04 02:25 UTC #2 lore raw

Quoted 24 lines · Stephen Rothwell

Hi [email protected],
Quoted 8 lines · On Fri, 30 Sep 2022 11:54:34 +0100 [email protected] wrote:
After merging the drm tree, today's linux-next build (x86_64 allmodconfig) failed like this:
/tmp/next/build/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
/tmp/next/build/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];
      |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~
Quoted 7 lines
cc1: all warnings being treated as errors
Caused by
5d8c3e836fc224 ("drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()")
I have reverted that commit for today.
I am still getting this failure. The full error is:
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]

Quoted 9 lines

  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];
      |                                  ^~~~~~~~~~~~~~

I'm not seeing it here, what gcc is this with?

Dave.

Stephen Rothwell

2022-10-04 03:06 UTC #3 lore raw

Hi Dave,

Quoted 34 lines · On Tue, 4 Oct 2022 12:24:37 +1000 David Airlie <[email protected]> wrote:

Quoted 22 lines · Stephen Rothwell
Quoted 8 lines · On Fri, 30 Sep 2022 11:54:34 +0100 [email protected] wrote:
After merging the drm tree, today's linux-next build (x86_64 allmodconfig) failed like this:
/tmp/next/build/drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c: In function 'dc_stream_remove_writeback':
/tmp/next/build/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];
      |                                 ~~~~~~~~~~~~~~~~~~~~~~^~~
Quoted 7 lines
cc1: all warnings being treated as errors
Caused by
5d8c3e836fc224 ("drm/amd/display: fix array-bounds error in dc_stream_remove_writeback()")
I have reverted that commit for today.
I am still getting this failure. The full error is:
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]
Quoted 9 lines
  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];
      |                                  ^~~~~~~~~~~~~~  

Quoted 1 line

I'm not seeing it here, what gcc is this with?

I am using an x86_64 cross compiler hosted on ppc64le - gcc v11.2.0 (on Debian).

Signature · 2 lines

Cheers,
Stephen Rothwell

Mark Brown

author maintainer

2022-10-04 11:39 UTC #4 lore raw

Quoted 7 lines · Stephen Rothwell

Quoted 3 lines · On Tue, 4 Oct 2022 12:24:37 +1000 David Airlie <[email protected]> wrote:
On Tue, Oct 4, 2022 at 12:21 PM Stephen Rothwell <[email protected]> wrote:
I'm not seeing it here, what gcc is this with?
I am using an x86_64 cross compiler hosted on ppc64le - gcc v11.2.0 (on Debian).

I was seeing this with an x86_64 cross compiler hosted on arm64 - Ubuntu 11.2.0-17ubuntu1 from the looks of it.

Alex Deucher

2022-10-05 15:30 UTC #5 lore raw

@Mahfooz, Hamza
@Aurabindo Pillai can you get this fixed up?

Thanks,

Alex

Quoted 12 lines · Mark Brown

Quoted 7 lines · Stephen Rothwell
Quoted 3 lines · On Tue, 4 Oct 2022 12:24:37 +1000 David Airlie <[email protected]> wrote:
On Tue, Oct 4, 2022 at 12:21 PM Stephen Rothwell <[email protected]> wrote:
I'm not seeing it here, what gcc is this with?
I am using an x86_64 cross compiler hosted on ppc64le - gcc v11.2.0 (on Debian).
I was seeing this with an x86_64 cross compiler hosted on arm64 - Ubuntu 11.2.0-17ubuntu1 from the looks of it.

Hamza Mahfooz

2022-10-05 16:45 UTC #6 lore raw

Quoted 3 lines · Alex Deucher

@Mahfooz, Hamza
@Aurabindo Pillai can you get this fixed up?

Seems like this is a false positive for GCC versions pre-12, because I'm not seeing this warning on GCC 12.2. However, we can fix this for older GCC versions with the following:

drivers/gpu/drm/amd/display/dc/dc_stream.h +1 -1

index 9e6025c98db9..67fede4bf248 100644
@@ -238,7 +238,7 @@ struct dc_stream_state {
 
 	/* writeback */
 	unsigned int num_wb_info;
-	struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
+	struct dc_writeback_info writeback_info[MAX_DWB_PIPES + 1];
 	const struct dc_transfer_func *func_shaper;
 	const struct dc_3dlut *lut3d_func;
 	/* Computed state bits */

Quoted 17 lines

Thanks,
Alex
Quoted 12 lines · Mark Brown
Quoted 7 lines · Stephen Rothwell
Quoted 3 lines · On Tue, 4 Oct 2022 12:24:37 +1000 David Airlie <[email protected]> wrote:
On Tue, Oct 4, 2022 at 12:21 PM Stephen Rothwell <[email protected]> wrote:
I'm not seeing it here, what gcc is this with?
I am using an x86_64 cross compiler hosted on ppc64le - gcc v11.2.0 (on Debian).
I was seeing this with an x86_64 cross compiler hosted on arm64 - Ubuntu 11.2.0-17ubuntu1 from the looks of it.

Signature · 1 line

Hamza

Stephen Rothwell

2022-10-05 22:28 UTC #7 lore raw

Hi all,

Quoted 14 lines · On Wed, 5 Oct 2022 12:45:31 -0400 Hamza Mahfooz <[email protected]> wrote:

Quoted 3 lines · Alex Deucher
@Mahfooz, Hamza
@Aurabindo Pillai can you get this fixed up?
Seems like this is a false positive for GCC versions pre-12, because I'm not seeing this warning on GCC 12.2. However, we can fix this for older GCC versions with the following:
drivers/gpu/drm/amd/display/dc/dc_stream.h +0 -0
index 9e6025c98db9..67fede4bf248 100644

drivers/gpu/drm/amd/display/dc/dc_stream.h struct dc_stream_state { · line 244

Quoted 8 lines

drivers/gpu/drm/amd/display/dc/dc_stream.h +1 -1

@@ -238,7 +238,7 @@ struct dc_stream_state {
 
  	/* writeback */
  	unsigned int num_wb_info;
-	struct dc_writeback_info writeback_info[MAX_DWB_PIPES];
+	struct dc_writeback_info writeback_info[MAX_DWB_PIPES + 1];
  	const struct dc_transfer_func *func_shaper;
  	const struct dc_3dlut *lut3d_func;
  	/* Computed state bits */

This is now in Linus' tree :-(

I have applied the following hack for today:

From: Stephen Rothwell <[email protected]>
Date: Thu, 6 Oct 2022 09:14:26 +1100
Subject: [PATCH] fix up for drivers/gpu/drm/amd/display/dc/core/dc_stream.c

Signed-off-by Stephen Rothwell <[email protected]>

---
 drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +2 -2

index ae13887756bf..a5da787b7876 100644
@@ -520,9 +520,9 @@ 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 && j < MAX_DWB_PIPES; i++) {
+	for (i = 0, j = 0; i < stream->num_wb_info && i < MAX_DWB_PIPES; i++) {
 		if (stream->writeback_info[i].wb_enabled) {
-			if (i != j)
+			if ((j >= 0) && (j < i))
 				/* trim the array */
 				stream->writeback_info[j] = stream->writeback_info[i];
 			j++;

Signature · 5 lines

2.35.1

-- 
Cheers,
Stephen Rothwell

Stephen Rothwell

2022-10-06 08:12 UTC #8 lore raw

Hi all,

Quoted 18 lines · On Thu, 6 Oct 2022 09:28:10 +1100 Stephen Rothwell <[email protected]> wrote:

I have applied the following hack for today:
From: Stephen Rothwell <[email protected]>
Date: Thu, 6 Oct 2022 09:14:26 +1100
Subject: [PATCH] fix up for drivers/gpu/drm/amd/display/dc/core/dc_stream.c
Signed-off-by Stephen Rothwell <[email protected]>
---
 drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/gpu/drm/amd/display/dc/core/dc_stream.c +0 -0
index ae13887756bf..a5da787b7876 100644
@@ -520,9 +520,9 @@ bool dc_stream_remove_writeback(struct dc *dc,
 	}

drivers/gpu/drm/amd/display/dc/core/dc_stream.c bool dc_stream_remove_writeback(struct dc *dc, · line 528

Quoted 10 lines

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +2 -2

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

This works as well, and (in my opinion) is better:

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +3 -3

index ae13887756bf..fb6222d4c430 100644
@@ -499,7 +499,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
 		struct dc_stream_state *stream,
 		uint32_t dwb_pipe_inst)
 {
-	int i = 0, j = 0;
+	unsigned int i, j;
 	if (stream == NULL) {
 		dm_error("DC: dc_stream is NULL!\n");
 		return false;

@@ -520,9 +520,9 @@ 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 && j < MAX_DWB_PIPES; i++) {
+	for (i = 0, j = 0; i < stream->num_wb_info; i++) {
 		if (stream->writeback_info[i].wb_enabled) {
-			if (i != j)
+			if (j < i)
 				/* trim the array */
 				stream->writeback_info[j] = stream->writeback_info[i];
 			j++;

Signature · 2 lines

Cheers,
Stephen Rothwell

Alex Deucher

2022-10-06 13:56 UTC #9 lore raw

This looks good to me. Care to add you s-o-b?

Alex

Quoted 64 lines · Stephen Rothwell

Hi all,

Quoted 18 lines · On Thu, 6 Oct 2022 09:28:10 +1100 Stephen Rothwell <[email protected]> wrote:

I have applied the following hack for today:
From: Stephen Rothwell <[email protected]>
Date: Thu, 6 Oct 2022 09:14:26 +1100
Subject: [PATCH] fix up for drivers/gpu/drm/amd/display/dc/core/dc_stream.c
Signed-off-by Stephen Rothwell <[email protected]>
---
 drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/gpu/drm/amd/display/dc/core/dc_stream.c +0 -0
index ae13887756bf..a5da787b7876 100644
@@ -520,9 +520,9 @@ bool dc_stream_remove_writeback(struct dc *dc,
      }

drivers/gpu/drm/amd/display/dc/core/dc_stream.c bool dc_stream_remove_writeback(struct dc *dc, · line 528

Quoted 10 lines

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +2 -2

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

This works as well, and (in my opinion) is better:

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +3 -4

index ae13887756bf..fb6222d4c430 100644
@@ -499,7 +499,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
                struct dc_stream_state *stream,
                uint32_t dwb_pipe_inst)
 {
-       int i = 0, j = 0;
+       unsigned int i, j;
        if (stream == NULL) {
                dm_error("DC: dc_stream is NULL!\n");
                return false;

@@ -520,9 +520,9 @@ 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 && j < MAX_DWB_PIPES; i++) {
+       for (i = 0, j = 0; i < stream->num_wb_info; i++) {
                if (stream->writeback_info[i].wb_enabled) {
-                       if (i != j)
+                       if (j < i)
                                /* trim the array */
                                stream->writeback_info[j] = stream->writeback_info[i];
                        j++;
 
--

Cheers,
Stephen Rothwell

Stephen Rothwell

2022-10-06 21:08 UTC #10 lore raw

Hi Alex,

Quoted 23 lines · On Thu, 6 Oct 2022 09:56:32 -0400 Alex Deucher <[email protected]> wrote:

This looks good to me. Care to add you s-o-b?

Quoted 19 lines · Stephen Rothwell

This works as well, and (in my opinion) is better:

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +1 -1

index ae13887756bf..fb6222d4c430 100644
@@ -499,7 +499,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
                struct dc_stream_state *stream,
                uint32_t dwb_pipe_inst)
 {
-       int i = 0, j = 0;
+       unsigned int i, j;
        if (stream == NULL) {
                dm_error("DC: dc_stream is NULL!\n");
                return false;

@@ -520,9 +520,9 @@ bool dc_stream_remove_writeback(struct dc *dc,
        }

Quoted 9 lines

drivers/gpu/drm/amd/display/dc/core/dc_stream.c bool dc_stream_remove_writeback(struct dc *dc, · line 528

Quoted 9 lines

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +2 -2

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

Signed-off-by Stephen Rothwell <[email protected]>

Signature · 2 lines

Cheers,
Stephen Rothwell

Hamza Mahfooz

2022-10-06 16:24 UTC #11 lore raw

In reply to Stephen Rothwell

Quoted 22 lines · Stephen Rothwell

Hi all,
Quoted 19 lines · On Thu, 6 Oct 2022 09:28:10 +1100 Stephen Rothwell <[email protected]> wrote:
I have applied the following hack for today:
From: Stephen Rothwell <[email protected]>
Date: Thu, 6 Oct 2022 09:14:26 +1100
Subject: [PATCH] fix up for drivers/gpu/drm/amd/display/dc/core/dc_stream.c
Signed-off-by Stephen Rothwell <[email protected]>
---
  drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)
drivers/gpu/drm/amd/display/dc/core/dc_stream.c +0 -0
index ae13887756bf..a5da787b7876 100644
@@ -520,9 +520,9 @@ bool dc_stream_remove_writeback(struct dc *dc,
  	}
 

Quoted 11 lines

drivers/gpu/drm/amd/display/dc/core/dc_stream.c bool dc_stream_remove_writeback(struct dc *dc, · line 528

Quoted 9 lines

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +2 -2

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

This works as well, and (in my opinion) is better:

I can confirm that this fix works on GCC 9.4, as well.

Quoted 27 lines

drivers/gpu/drm/amd/display/dc/core/dc_stream.c +3 -3

index ae13887756bf..fb6222d4c430 100644
@@ -499,7 +499,7 @@ bool dc_stream_remove_writeback(struct dc *dc,
  		struct dc_stream_state *stream,
  		uint32_t dwb_pipe_inst)
  {
-	int i = 0, j = 0;
+	unsigned int i, j;
  	if (stream == NULL) {
  		dm_error("DC: dc_stream is NULL!\n");
  		return false;

@@ -520,9 +520,9 @@ 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 && j < MAX_DWB_PIPES; i++) {
+	for (i = 0, j = 0; i < stream->num_wb_info; i++) {
  		if (stream->writeback_info[i].wb_enabled) {
-			if (i != j)
+			if (j < i)
  				/* trim the array */
  				stream->writeback_info[j] = stream->writeback_info[i];
  			j++;

Signature · 1 line

Hamza