Hi-- On 8/3/23 08:24, Adam Ford wrote: > On Thu, Aug 3, 2023 at 9:42 AM Aleksandr Nogikh <nogikh@xxxxxxxxxx> wrote: >> >> Hello, >> >> We've been seing the following linker error on arm64 syzbot instances: >> >> ld.lld: error: undefined symbol: phy_mipi_dphy_get_default_config_for_hsclk >>>>> referenced by samsung-dsim.c:731 (drivers/gpu/drm/bridge/samsung-dsim.c:731) >>>>> drivers/gpu/drm/bridge/samsung-dsim.o:(samsung_dsim_init) in archive vmlinux.a >> >> Steps to reproduce on the latest linux-next: >> >> $ git checkout next-20230803 >> $ wget -O '.config' 'https://raw.githubusercontent.com/google/syzkaller/master/dashboard/config/linux/upstream-arm64-kasan.config' >> $ make CC=clang ARCH=arm64 LD=ld.lld CROSS_COMPILE=aarch64-linux-gnu- olddefconfig >> >> This also prints: >> >> WARNING: unmet direct dependencies detected for GENERIC_PHY_MIPI_DPHY >> Depends on [n]: GENERIC_PHY [=n] >> Selected by [y]: >> - DRM_NWL_MIPI_DSI [=y] && DRM_BRIDGE [=y] && DRM [=y] && COMMON_CLK [=y] && OF [=y] && HAS_IOMEM [=y] >> - DRM_SAMSUNG_DSIM [=y] && DRM [=y] && DRM_BRIDGE [=y] && COMMON_CLK [=y] && OF [=y] && HAS_IOMEM [=y] >> >> $ make CC=clang ARCH=arm64 LD=ld.lld CROSS_COMPILE=aarch64-linux-gnu- -j$(nproc) >> >> The kernel should have still compiled fine even despite the message above, right? No. See drivers/Makefile: obj-$(CONFIG_GENERIC_PHY) += phy/ so the drivers/phy/ subdir is only built when CONFIG_GENERIC_PHY is set, but it's not set. >> Could you please take a look? > > GENERIC_PHY_MIPI_DPHY was enabled to use > phy_mipi_dphy_get_default_config() which takes in the pixel clock, > bits-per-pixel, number of lanes and phy structure. It applies a bunch > of math based on the info passed and fills in the structure, but that > function itself doesn't appear to be referencing phy code, so it's > likely safe. > > I think this can be resolved by enabling GENERIC_PHY. I just checked > linux-next and when I built the arm64 defconfig, it enables > GENERIC_PHY=y, so I don't think this is an issue. I also checked the defconfig doesn't matter in this case. The .config that was provided has: # CONFIG_GENERIC_PHY is not set CONFIG_GENERIC_PHY_MIPI_DPHY=y but yes, selecting GENERIC_PHY (needed in 3 places) does fix the warnings and build error. 2 instance in drm/bridge/Kconfig and one in drm/bridge/cadence/Kconfig (found by inspection). > multi_v7_defconfig for ARM and it also sets GENERIC_PHY=y for 32-bit > ARM people using some of the Exynos boards. > > I don't know what version of Linux you're trying to build, but I can't > replicate your issue. I had no problem replicating the kconfig warnings and build error. -- ~Randy
