Messages in this thread | | | Date | Mon, 22 Jun 2020 15:52:37 -0700 | From | Fangrui Song <> | Subject | Re: [PATCH v2 1/3] vmlinux.lds.h: Add .gnu.version* to DISCARDS |
| |
On 2020-06-22, Kees Cook wrote: >On Mon, Jun 22, 2020 at 03:00:43PM -0700, Fangrui Song wrote: >> On 2020-06-22, Kees Cook wrote: >> > For vmlinux linking, no architecture uses the .gnu.version* section, >> > so remove it via the common DISCARDS macro in preparation for adding >> > --orphan-handling=warn more widely. >> > >> > Signed-off-by: Kees Cook <keescook@chromium.org> >> > --- >> > include/asm-generic/vmlinux.lds.h | 1 + >> > 1 file changed, 1 insertion(+) >> > >> > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h >> > index db600ef218d7..6fbe9ed10cdb 100644 >> > --- a/include/asm-generic/vmlinux.lds.h >> > +++ b/include/asm-generic/vmlinux.lds.h >> > @@ -934,6 +934,7 @@ >> > *(.discard) \ >> > *(.discard.*) \ >> > *(.modinfo) \ >> > + *(.gnu.version*) \ >> > } >> > >> > /** >> > -- >> > 2.25.1 >> >> I wonder what lead to .gnu.version{,_d,_r} sections in the kernel. > >This looks like a bug in bfd.ld? There are no versioned symbols in any >of the input files (and no output section either!) > >The link command is: >$ ld -m elf_x86_64 --no-ld-generated-unwind-info -z noreloc-overflow -pie \ >--no-dynamic-linker --orphan-handling=warn -T \ >arch/x86/boot/compressed/vmlinux.lds \ >arch/x86/boot/compressed/kernel_info.o \ >arch/x86/boot/compressed/head_64.o arch/x86/boot/compressed/misc.o \ >arch/x86/boot/compressed/string.o arch/x86/boot/compressed/cmdline.o \ >arch/x86/boot/compressed/error.o arch/x86/boot/compressed/piggy.o \ >arch/x86/boot/compressed/cpuflags.o \ >arch/x86/boot/compressed/early_serial_console.o \ >arch/x86/boot/compressed/kaslr.o arch/x86/boot/compressed/kaslr_64.o \ >arch/x86/boot/compressed/mem_encrypt.o \ >arch/x86/boot/compressed/pgtable_64.o arch/x86/boot/compressed/acpi.o \ >-o arch/x86/boot/compressed/vmlinux > >None of the inputs have the section: > >$ for i in arch/x86/boot/compressed/kernel_info.o \ >arch/x86/boot/compressed/head_64.o arch/x86/boot/compressed/misc.o \ >arch/x86/boot/compressed/string.o arch/x86/boot/compressed/cmdline.o \ >arch/x86/boot/compressed/error.o arch/x86/boot/compressed/piggy.o \ >arch/x86/boot/compressed/cpuflags.o \ >arch/x86/boot/compressed/early_serial_console.o \ >arch/x86/boot/compressed/kaslr.o arch/x86/boot/compressed/kaslr_64.o \ >arch/x86/boot/compressed/mem_encrypt.o \ >arch/x86/boot/compressed/pgtable_64.o arch/x86/boot/compressed/acpi.o \ >; do echo -n $i": "; readelf -Vs $i | grep 'version'; done >arch/x86/boot/compressed/kernel_info.o: No version information found in this file. >arch/x86/boot/compressed/head_64.o: No version information found in this file. >arch/x86/boot/compressed/misc.o: No version information found in this file. >arch/x86/boot/compressed/string.o: No version information found in this file. >arch/x86/boot/compressed/cmdline.o: No version information found in this file. >arch/x86/boot/compressed/error.o: No version information found in this file. >arch/x86/boot/compressed/piggy.o: No version information found in this file. >arch/x86/boot/compressed/cpuflags.o: No version information found in this file. >arch/x86/boot/compressed/early_serial_console.o: No version information found in this file. >arch/x86/boot/compressed/kaslr.o: No version information found in this file. >arch/x86/boot/compressed/kaslr_64.o: No version information found in this file. >arch/x86/boot/compressed/mem_encrypt.o: No version information found in this file. >arch/x86/boot/compressed/pgtable_64.o: No version information found in this file. >arch/x86/boot/compressed/acpi.o: No version information found in this file. > >And it's not in the output: > >$ readelf -Vs arch/x86/boot/compressed/vmlinux | grep version >No version information found in this file. > >So... for the kernel we need to silence it right now.
Re-link with -M (or -Map file) to check where .gnu.version{,_d,_r} input sections come from?
If it is a bug, we should probably figure out which version of binutils has fixed the bug.
| |