On Feb 24, 2025, at 7:12 AM, Arnd Bergmann <arnd@xxxxxxxxxx> wrote: > The definition of get_dump_page() is guarded by CONFIG_ELF_CORE, but > the caller has now moved into a function that is built based on > CONFIG_COREDUMP, which leads to a possible link failure: > > ld.lld-21: error: undefined symbol: get_dump_page >>>> referenced by coredump.c >>>> fs/coredump.o:(dump_vma_snapshot) in archive vmlinux.a Kernel test robot reported this issue yesterday here: https://lore.kernel.org/oe-kbuild-all/202502231914.ROOVWMZN-lkp@xxxxxxxxx/ https://lore.kernel.org/oe-kbuild-all/202502231818.fP8cuxmf-lkp@xxxxxxxxx/ > Change the #ifdef block around the definition to match the caller. > In practice there is very little difference, as setting COREDUMP > but not ELF_CORE is not useful. Good catch! I wonder if we should guard the sparse dump size calculation logic from the get_dump_page() caller behind CONFIG_ELF_CORE instead though. I guess the question becomes, will we ever have a non-ELF core dump format that won't skip zero pages? Anyway, I'm fine with this fix as-is.
