On 8/3/23 19:42, Adam Ford wrote: > On Thu, Aug 3, 2023 at 9:37 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: >> >> >> >> On 8/3/23 19:26, Adam Ford wrote: >>> On Thu, Aug 3, 2023 at 9:01 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: >>>> >>>> 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 >>>> >>> >>> Where/how was the .config generated? >>> >> >> Aleksandr posted a link to the config file above. > > I get that, but I am not sure how this was generated. > Nor am I. Alexsandr can hopefully tell us. >> >>> Are you building linux-next or something else? The .config file >>> generated when I build the arm64 defconfig show both enabled: >> >> linux-next. >> >> >>> $ grep GENERIC_PHY .config >>> CONFIG_GENERIC_PHY=y >>> CONFIG_GENERIC_PHY_MIPI_DPHY=y >>> >> >> Yes, this is not a defconfig file. > > I know, but it is a .config file that is generated from make defconfig > ARCH=arm64 >> Not necessarily. It could be generated by 'make randconfig'. >>> >>>> 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. >>> >>> If you can replicate the problem, I'd suggest submitting a patch. >> >> Sure, I'll do that. > > Great! thanks. > > adam >> >> -- >> ~Randy -- ~Randy
