| Message ID | 20240212-fix-elf-type-btf-vmlinux-bin-o-big-endian-v2-1-22c0a6352069@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] kbuild: Fix changing ELF file type for output of gen_btf for big endian | expand |
On Tue, Feb 13, 2024 at 11:06 AM Nathan Chancellor <nathan@kernel.org> wrote: > > Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works > fine for little endian platforms: > > 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > However, for big endian platforms, it changes the wrong byte, resulting > in an invalid ELF file type, which ld.lld rejects: > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > Type: <unknown>: 103 > > ld.lld: error: .btf.vmlinux.bin.o: unknown file type > > Fix this by updating the entire 16-bit e_type field rather than just a > single byte, so that everything works correctly for all platforms and > linkers. > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > Type: REL (Relocatable file) > > While in the area, update the comment to mention that binutils 2.35+ > matches LLD's behavior of rejecting an ET_EXEC input, which occurred > after the comment was added. > > Cc: stable@vger.kernel.org > Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > Link: https://github.com/llvm/llvm-project/pull/75643 > Suggested-by: Masahiro Yamada <masahiroy@kernel.org> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> Thanks. I will wait for a few days until the reviewers come back to give Reviewed-by again. > --- > Changes in v2: > - Rather than change the seek value for dd, update the entire e_type > field (Masahiro). Due to this change, I did not carry forward the > tags of v1. > - Slightly update commit message to remove mention of ET_EXEC, which > does not match the dump (Masahiro). > - Update comment to mention binutils 2.35+ has the same behavior as LLD > (Fangrui). > - Link to v1: https://lore.kernel.org/r/20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-v1-1-cb3112491edc@kernel.org > --- > scripts/link-vmlinux.sh | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh > index a432b171be82..7862a8101747 100755 > --- a/scripts/link-vmlinux.sh > +++ b/scripts/link-vmlinux.sh > @@ -135,8 +135,13 @@ gen_btf() > ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ > --strip-all ${1} ${2} 2>/dev/null > # Change e_type to ET_REL so that it can be used to link final vmlinux. > - # Unlike GNU ld, lld does not allow an ET_EXEC input. > - printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none > + # GNU ld 2.35+ and lld do not allow an ET_EXEC input. > + if is_enabled CONFIG_CPU_BIG_ENDIAN; then > + et_rel='\0\1' > + else > + et_rel='\1\0' > + fi > + printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none > } > > # Create ${2} .S file with all symbols from the ${1} object file > > --- > base-commit: 54be6c6c5ae8e0d93a6c4641cb7528eb0b6ba478 > change-id: 20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-dbc55a1e1296 > > Best regards, > -- > Nathan Chancellor <nathan@kernel.org> > >
On Mon, Feb 12, 2024 at 6:16 PM Masahiro Yamada <masahiroy@kernel.org> wrote: > > On Tue, Feb 13, 2024 at 11:06 AM Nathan Chancellor <nathan@kernel.org> wrote: > > > > Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > > changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works > > fine for little endian platforms: > > > > 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > > > However, for big endian platforms, it changes the wrong byte, resulting > > in an invalid ELF file type, which ld.lld rejects: > > > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > > > Type: <unknown>: 103 > > > > ld.lld: error: .btf.vmlinux.bin.o: unknown file type > > > > Fix this by updating the entire 16-bit e_type field rather than just a > > single byte, so that everything works correctly for all platforms and > > linkers. > > > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > > > Type: REL (Relocatable file) > > > > While in the area, update the comment to mention that binutils 2.35+ > > matches LLD's behavior of rejecting an ET_EXEC input, which occurred > > after the comment was added. > > > > Cc: stable@vger.kernel.org > > Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > > Link: https://github.com/llvm/llvm-project/pull/75643 > > Suggested-by: Masahiro Yamada <masahiroy@kernel.org> > > Signed-off-by: Nathan Chancellor <nathan@kernel.org> Thanks for updating the comment. Reviewed-by: Fangrui Song <maskray@google.com> > > Thanks. > > I will wait for a few days until > the reviewers come back to give Reviewed-by again. > > > > > > > --- > > Changes in v2: > > - Rather than change the seek value for dd, update the entire e_type > > field (Masahiro). Due to this change, I did not carry forward the > > tags of v1. > > - Slightly update commit message to remove mention of ET_EXEC, which > > does not match the dump (Masahiro). > > - Update comment to mention binutils 2.35+ has the same behavior as LLD > > (Fangrui). > > - Link to v1: https://lore.kernel.org/r/20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-v1-1-cb3112491edc@kernel.org > > --- > > scripts/link-vmlinux.sh | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh > > index a432b171be82..7862a8101747 100755 > > --- a/scripts/link-vmlinux.sh > > +++ b/scripts/link-vmlinux.sh > > @@ -135,8 +135,13 @@ gen_btf() > > ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ > > --strip-all ${1} ${2} 2>/dev/null > > # Change e_type to ET_REL so that it can be used to link final vmlinux. > > - # Unlike GNU ld, lld does not allow an ET_EXEC input. > > - printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none > > + # GNU ld 2.35+ and lld do not allow an ET_EXEC input. > > + if is_enabled CONFIG_CPU_BIG_ENDIAN; then > > + et_rel='\0\1' > > + else > > + et_rel='\1\0' > > + fi > > + printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none > > } > > > > # Create ${2} .S file with all symbols from the ${1} object file > > > > --- > > base-commit: 54be6c6c5ae8e0d93a6c4641cb7528eb0b6ba478 > > change-id: 20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-dbc55a1e1296 > > > > Best regards, > > -- > > Nathan Chancellor <nathan@kernel.org> > > > > > > > -- > Best Regards > Masahiro Yamada >
On Tue 13 Feb 2024 11:15:40 GMT, Masahiro Yamada wrote: > On Tue, Feb 13, 2024 at 11:06 AM Nathan Chancellor > <nathan@kernel.org> wrote: > > > > Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > > changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works > > fine for little endian platforms: > > > > 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > > > However, for big endian platforms, it changes the wrong byte, resulting > > in an invalid ELF file type, which ld.lld rejects: > > > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > > > Type: <unknown>: 103 > > > > ld.lld: error: .btf.vmlinux.bin.o: unknown file type > > > > Fix this by updating the entire 16-bit e_type field rather than just a > > single byte, so that everything works correctly for all platforms and > > linkers. > > > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > > > Type: REL (Relocatable file) > > > > While in the area, update the comment to mention that binutils 2.35+ > > matches LLD's behavior of rejecting an ET_EXEC input, which occurred > > after the comment was added. > > > > Cc: stable@vger.kernel.org > > Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > > Link: https://github.com/llvm/llvm-project/pull/75643 > > Suggested-by: Masahiro Yamada <masahiroy@kernel.org> > > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > > > Thanks. > > I will wait for a few days until > the reviewers come back to give Reviewed-by again. thanks, v2 looks even better. Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> > > --- > > Changes in v2: > > - Rather than change the seek value for dd, update the entire e_type > > field (Masahiro). Due to this change, I did not carry forward the > > tags of v1. > > - Slightly update commit message to remove mention of ET_EXEC, which > > does not match the dump (Masahiro). > > - Update comment to mention binutils 2.35+ has the same behavior as LLD > > (Fangrui). > > - Link to v1: https://lore.kernel.org/r/20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-v1-1-cb3112491edc@kernel.org > > --- > > scripts/link-vmlinux.sh | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh > > index a432b171be82..7862a8101747 100755 > > --- a/scripts/link-vmlinux.sh > > +++ b/scripts/link-vmlinux.sh > > @@ -135,8 +135,13 @@ gen_btf() > > ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ > > --strip-all ${1} ${2} 2>/dev/null > > # Change e_type to ET_REL so that it can be used to link final vmlinux. > > - # Unlike GNU ld, lld does not allow an ET_EXEC input. > > - printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none > > + # GNU ld 2.35+ and lld do not allow an ET_EXEC input. > > + if is_enabled CONFIG_CPU_BIG_ENDIAN; then > > + et_rel='\0\1' > > + else > > + et_rel='\1\0' > > + fi > > + printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none > > } > > > > # Create ${2} .S file with all symbols from the ${1} object file > > > > --- > > base-commit: 54be6c6c5ae8e0d93a6c4641cb7528eb0b6ba478 > > change-id: 20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-dbc55a1e1296 > > > > Best regards, > > -- > > Nathan Chancellor <nathan@kernel.org> > > > > > > > -- > Best Regards > Masahiro Yamada
On Mon, Feb 12, 2024 at 07:05:10PM -0700, Nathan Chancellor wrote: > Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works > fine for little endian platforms: > > 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > However, for big endian platforms, it changes the wrong byte, resulting > in an invalid ELF file type, which ld.lld rejects: > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > Type: <unknown>: 103 > > ld.lld: error: .btf.vmlinux.bin.o: unknown file type > > Fix this by updating the entire 16-bit e_type field rather than just a > single byte, so that everything works correctly for all platforms and > linkers. > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > Type: REL (Relocatable file) > > While in the area, update the comment to mention that binutils 2.35+ > matches LLD's behavior of rejecting an ET_EXEC input, which occurred > after the comment was added. > > Cc: stable@vger.kernel.org > Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > Link: https://github.com/llvm/llvm-project/pull/75643 > Suggested-by: Masahiro Yamada <masahiroy@kernel.org> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> Writing the u16 looks fine to me. Reviewed-by: Kees Cook <keescook@chromium.org>
Hi, On Mon, Feb 12, 2024 at 07:05:10PM -0700, Nathan Chancellor wrote: > Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works > fine for little endian platforms: > > 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > However, for big endian platforms, it changes the wrong byte, resulting > in an invalid ELF file type, which ld.lld rejects: > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > Type: <unknown>: 103 > > ld.lld: error: .btf.vmlinux.bin.o: unknown file type > > Fix this by updating the entire 16-bit e_type field rather than just a > single byte, so that everything works correctly for all platforms and > linkers. > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > Type: REL (Relocatable file) > > While in the area, update the comment to mention that binutils 2.35+ > matches LLD's behavior of rejecting an ET_EXEC input, which occurred > after the comment was added. > > Cc: stable@vger.kernel.org > Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > Link: https://github.com/llvm/llvm-project/pull/75643 > Suggested-by: Masahiro Yamada <masahiroy@kernel.org> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> I prefer this version to v1 as well. This seems better than setting the seek value. Reviewed-by: Justin Stitt <justinstitt@google.com> > --- > Changes in v2: > - Rather than change the seek value for dd, update the entire e_type > field (Masahiro). Due to this change, I did not carry forward the > tags of v1. > - Slightly update commit message to remove mention of ET_EXEC, which > does not match the dump (Masahiro). > - Update comment to mention binutils 2.35+ has the same behavior as LLD > (Fangrui). > - Link to v1: https://lore.kernel.org/r/20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-v1-1-cb3112491edc@kernel.org > --- > scripts/link-vmlinux.sh | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh > index a432b171be82..7862a8101747 100755 > --- a/scripts/link-vmlinux.sh > +++ b/scripts/link-vmlinux.sh > @@ -135,8 +135,13 @@ gen_btf() > ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ > --strip-all ${1} ${2} 2>/dev/null > # Change e_type to ET_REL so that it can be used to link final vmlinux. > - # Unlike GNU ld, lld does not allow an ET_EXEC input. > - printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none > + # GNU ld 2.35+ and lld do not allow an ET_EXEC input. > + if is_enabled CONFIG_CPU_BIG_ENDIAN; then > + et_rel='\0\1' > + else > + et_rel='\1\0' > + fi > + printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none > } > > # Create ${2} .S file with all symbols from the ${1} object file > > --- > base-commit: 54be6c6c5ae8e0d93a6c4641cb7528eb0b6ba478 > change-id: 20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-dbc55a1e1296 > > Best regards, > -- > Nathan Chancellor <nathan@kernel.org> > Thanks Justin
On Tue, Feb 13, 2024 at 11:06 AM Nathan Chancellor <nathan@kernel.org> wrote: > > Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works > fine for little endian platforms: > > 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| > > However, for big endian platforms, it changes the wrong byte, resulting > in an invalid ELF file type, which ld.lld rejects: > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > Type: <unknown>: 103 > > ld.lld: error: .btf.vmlinux.bin.o: unknown file type > > Fix this by updating the entire 16-bit e_type field rather than just a > single byte, so that everything works correctly for all platforms and > linkers. > > 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| > -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| > > Type: REL (Relocatable file) > > While in the area, update the comment to mention that binutils 2.35+ > matches LLD's behavior of rejecting an ET_EXEC input, which occurred > after the comment was added. > > Cc: stable@vger.kernel.org > Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") > Link: https://github.com/llvm/llvm-project/pull/75643 > Suggested-by: Masahiro Yamada <masahiroy@kernel.org> > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- Applied to linux-kbuild/fixes. Thanks.
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index a432b171be82..7862a8101747 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -135,8 +135,13 @@ gen_btf() ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ --strip-all ${1} ${2} 2>/dev/null # Change e_type to ET_REL so that it can be used to link final vmlinux. - # Unlike GNU ld, lld does not allow an ET_EXEC input. - printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none + # GNU ld 2.35+ and lld do not allow an ET_EXEC input. + if is_enabled CONFIG_CPU_BIG_ENDIAN; then + et_rel='\0\1' + else + et_rel='\1\0' + fi + printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none } # Create ${2} .S file with all symbols from the ${1} object file
Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works fine for little endian platforms: 00000000 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 |.ELF............| -00000010 03 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| +00000010 01 00 b7 00 01 00 00 00 00 00 00 80 00 80 ff ff |................| However, for big endian platforms, it changes the wrong byte, resulting in an invalid ELF file type, which ld.lld rejects: 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| +00000010 01 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| Type: <unknown>: 103 ld.lld: error: .btf.vmlinux.bin.o: unknown file type Fix this by updating the entire 16-bit e_type field rather than just a single byte, so that everything works correctly for all platforms and linkers. 00000000 7f 45 4c 46 02 02 01 00 00 00 00 00 00 00 00 00 |.ELF............| -00000010 00 03 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| +00000010 00 01 00 16 00 00 00 01 00 00 00 00 00 10 00 00 |................| Type: REL (Relocatable file) While in the area, update the comment to mention that binutils 2.35+ matches LLD's behavior of rejecting an ET_EXEC input, which occurred after the comment was added. Cc: stable@vger.kernel.org Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF") Link: https://github.com/llvm/llvm-project/pull/75643 Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- Changes in v2: - Rather than change the seek value for dd, update the entire e_type field (Masahiro). Due to this change, I did not carry forward the tags of v1. - Slightly update commit message to remove mention of ET_EXEC, which does not match the dump (Masahiro). - Update comment to mention binutils 2.35+ has the same behavior as LLD (Fangrui). - Link to v1: https://lore.kernel.org/r/20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-v1-1-cb3112491edc@kernel.org --- scripts/link-vmlinux.sh | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- base-commit: 54be6c6c5ae8e0d93a6c4641cb7528eb0b6ba478 change-id: 20240208-fix-elf-type-btf-vmlinux-bin-o-big-endian-dbc55a1e1296 Best regards,