Hi Am 28.10.25 um 03:55 schrieb LiangCheng Wang:
The DRM_GEM_SHMEM_HELPER helper requires MMU enabled because it uses vmf_insert_pfn() in its mmap implementation. On NOMMU configurations (e.g. some RISC-V randconfig builds), this symbol is unavailable and selecting DRM_GEM_SHMEM_HELPER causes a modpost undefined reference:ERROR: modpost: "vmf_insert_pfn" [drivers/gpu/drm/drm_shmem_helper.ko] undefined! Normally, Kconfig prevents this helper from being selected when CONFIG_MMU=n. However, in some randconfig builds (such as those used by 0day CI), select statements can override unmet dependencies, triggering the issue. Add an explicit dependency on MMU to DRM_PIXPAPER to prevent this. Reported-by: kernel test robot <[email protected]> Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ Fixes: 0c4932f6ddf8 ("drm/tiny: pixpaper: Fix missing dependency on DRM_GEM_SHMEM_HELPER") Signed-off-by: LiangCheng Wang <[email protected]> --- This patch fixes a build issue reported by the kernel test robot when building with CONFIG_MMU=n on RISC-V randconfig. In such configurations, the DRM_GEM_SHMEM_HELPER helper uses vmf_insert_pfn(), which is unavailable without MMU support. Although normal Kconfig rules prevent DRM_GEM_SHMEM_HELPER from being selected in this case, randconfig builds may forcibly enable it via select, leading to the following modpost error: ERROR: modpost: "vmf_insert_pfn" [drivers/gpu/drm/drm_shmem_helper.ko] undefined! The fix is to add an explicit `depends on MMU` to the DRM_PIXPAPER driver, ensuring it cannot be built for NOMMU systems. This issue cannot always be reproduced locally because typical builds do not violate Kconfig dependencies, but it was confirmed that the fix prevents the reported 0day failure.
The problem most likely comes from [1]. Is it possible to fix this instead? [1] https://elixir.bootlin.com/linux/v6.17.5/source/arch/riscv/Kconfig#L1345 Best regards Thomas
--- LiangCheng Wang (1): drm/tiny: pixpaper: add explicit dependency on MMU drivers/gpu/drm/tiny/Kconfig Signed-off-by: LiangCheng Wang <[email protected]> --- drivers/gpu/drm/tiny/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig index 7d9e85e932d7fd7bdb6ad7a4c6ba0f835841f623..f0e72d4b6a4709564e63c758e857bdb4a320dbe7 100644 --- a/drivers/gpu/drm/tiny/Kconfig +++ b/drivers/gpu/drm/tiny/Kconfig @@ -85,6 +85,7 @@ config DRM_PANEL_MIPI_DBI config DRM_PIXPAPER tristate "DRM support for PIXPAPER display panels" depends on DRM && SPI + depends on MMU select DRM_CLIENT_SELECTION select DRM_GEM_SHMEM_HELPER select DRM_KMS_HELPER --- base-commit: fd57572253bc356330dbe5b233c2e1d8426c66fd change-id: 20251028-bar-ae0d85b16f13 Best regards,
-- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)
