Re: [REGRESSION] drm/amd/display: amdgpu_dm_plane_test.ko fails to build due to modpost "too long symbol"

[Venkat Rao Bagalkote <venkat88@linux.ibm.com>]

On 10/07/26 10:45 am, Venkat Rao Bagalkote wrote:
>
> On 09/07/26 11:53 pm, Randy Dunlap wrote:
>>
>> On 7/7/26 10:05 PM, Venkat Rao Bagalkote wrote:
>>> Greetings!!!
>>>
>>> linux-next is failing to build for me with:
>>>
>>> ERROR: modpost: too long symbol
>>> "amdgpu_dm_plane_fill_gfx9_plane_attributes_from_modifiers"
>>> [drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/tests/amdgpu_dm_plane_test.ko] 
>>>
>>>
>>> make[2]: *** [scripts/Makefile.modpost:147: Module.symvers] Error 1
>>> make[1]: *** [Makefile:2165: modpost] Error 2
>>> make: *** [Makefile:248: __sub-make] Error 2
>>>
>>> The failure occurs during modpost while building:
>>>
>>> drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_plane_test.ko
>>>
>>> This appears to be a regression in the AMD display KUnit test code.
>>>
>>> Could someone please take a look?
>>>
>>>
>>> If you happen to fix this, please add below tag.
>>>
>>> Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
>> Hi,
>> I cannot reproduce this when using gcc v15.3.0.
>>
>> Which compiler & version are you using?
>>
> Hello,
>
> I am seeing this across below mentioned gcc version.
>
>
> gcc (GCC) 14.3.1 20251022 (Red Hat 14.3.1-4)
> gcc (GCC) 11.5.0 20240719 (Red Hat 11.5.0-11)
> gcc (GCC) 12.2.1 20221121 (Red Hat 12.2.1-7)
>
>
> Attched is the .config file.

Git bisect is pointing to below commit as first bad commit.


# git bisect bad
2b147895be109e0860269a7a72c697cdf049a885 is the first bad commit
commit 2b147895be109e0860269a7a72c697cdf049a885 (HEAD)
Author: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Date:   Fri Jun 12 16:12:21 2026 -0400

     drm/amd/display: Add kunit tests for amdgpu_dm_plane

     Add kunit tests for some functions in amdgpu_dm_plane.

     Assisted-by: Copilot:Claude-Opus-4.8
     Reviewed-by: Alex Hung <alex.hung@amd.com>
     Signed-off-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
     Signed-off-by: George Zhang <george.zhang@amd.com>
     Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c   |  115 
++++++-----
  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.h   |   51 +++++
  drivers/gpu/drm/amd/display/amdgpu_dm/tests/Makefile  |    2 +
  drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_plane_test.c | 
1204 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  4 files changed, 1325 insertions(+), 47 deletions(-)
  create mode 100644 
drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_plane_test.c


# git bisect log
git bisect start
# status: waiting for both good and bad commits
# bad: [5c73cd9f0819c1c44e373e3dabb68318b1de1a12] Add linux-next 
specific files for 20260707
git bisect bad 5c73cd9f0819c1c44e373e3dabb68318b1de1a12
# good: [8cdeaa50eae8dad34885515f62559ee83e7e8dda] Linux 7.2-rc2
git bisect good 8cdeaa50eae8dad34885515f62559ee83e7e8dda
# good: [aac7863446a8e0cf380f4a5087bc3cdc9b8c14c0] Merge branch 'master' 
of https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
git bisect good aac7863446a8e0cf380f4a5087bc3cdc9b8c14c0
# bad: [fe28d02cde5372d7f71cc6132ccdef37a98ac750] Merge branch 
'for-linux-next' of https://gitlab.freedesktop.org/drm/i915/kernel.git
git bisect bad fe28d02cde5372d7f71cc6132ccdef37a98ac750
# good: [0639cb26862afe4e35a689a8b5df8b9117c19f52] Merge tag 
'drm-xe-next-2026-07-03' of https://gitlab.freedesktop.org/drm/xe/kernel 
into drm-next
git bisect good 0639cb26862afe4e35a689a8b5df8b9117c19f52
# good: [4e9c8a9c322427055c4892183d266ba391af1bc8] drm/amdkfd: drop 
struct kfd_signal_page wrapper
git bisect good 4e9c8a9c322427055c4892183d266ba391af1bc8
# bad: [ea33aa1545535fdb4c1a208b7bfd63314c3a4aa2] drm/amdgpu: Drop 
legacy ACA log RAS error data code
git bisect bad ea33aa1545535fdb4c1a208b7bfd63314c3a4aa2
# good: [a17e79d01f22182a9fcbe79fcbe2ad1477d43e0f] drm/amd/pm: Validate 
pp_table header before reading size
git bisect good a17e79d01f22182a9fcbe79fcbe2ad1477d43e0f
# bad: [7a561c2b1b63abcffb55f625c0d0adb68ab2961a] drm/amd/display: 
Simplify boolean checks
git bisect bad 7a561c2b1b63abcffb55f625c0d0adb68ab2961a
# good: [53ef33c084c5778cc2dcd1efff25e31b6e231141] drm/amd/pm: Validate 
Tonga PPTable subtable bounds
git bisect good 53ef33c084c5778cc2dcd1efff25e31b6e231141
# good: [fe5966d4fdcbed91e6b3478ea6c89d9915d6ed4a] drm/amdkfd: move 
TBA/TMA from system to device memory
git bisect good fe5966d4fdcbed91e6b3478ea6c89d9915d6ed4a
# good: [7a39b1c3b2e6b27f4230a20ccf9ac5a2737fa8b0] drm/amd/display: 
Replace repeated no-native-i2c checks with force_i2c_over_aux field
git bisect good 7a39b1c3b2e6b27f4230a20ccf9ac5a2737fa8b0
# good: [88ae862060f05cd8279e764832f04eafafa505d8] drm/amd/display: Add 
more KUnit tests for amdgpu_dm_colorop
git bisect good 88ae862060f05cd8279e764832f04eafafa505d8
# bad: [2b147895be109e0860269a7a72c697cdf049a885] drm/amd/display: Add 
kunit tests for amdgpu_dm_plane
git bisect bad 2b147895be109e0860269a7a72c697cdf049a885
# first bad commit: [2b147895be109e0860269a7a72c697cdf049a885] 
drm/amd/display: Add kunit tests for amdgpu_dm_plane

>
>
> Regards,
>
> Venkat.