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. > > > 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 > > > > >> 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
