[PATCH 2/3] kbuild: Add '.rel.*' strip pattern for vmlinux

Nathan Chancellor posted 3 patches 2 months, 1 week ago
[PATCH 2/3] kbuild: Add '.rel.*' strip pattern for vmlinux
Posted by Nathan Chancellor 2 months, 1 week ago
Prior to binutils commit c12d9fa2afe ("Support objcopy
--remove-section=.relaFOO") [1] in 2.32, stripping relocation sections
required the trailing period (i.e., '.rel.*') to work properly.

After commit 3e86e4d74c04 ("kbuild: keep .modinfo section in
vmlinux.unstripped"), there is an error with binutils 2.31.1 or earlier
because these sections are not properly removed:

  s390-linux-objcopy: st6tO8Ev: symbol `.modinfo' required but not present
  s390-linux-objcopy:st6tO8Ev: no symbols

Add the old pattern to resolve this issue (along with a comment to allow
cleaning this when binutils 2.32 or newer is the minimum supported
version). While the aforementioned kbuild change exposes this, the
pattern was originally changed by commit 71d815bf5dfd ("kbuild: Strip
runtime const RELA sections correctly"), where it would still be
incorrect with binutils older than 2.32.

Fixes: 71d815bf5dfd ("kbuild: Strip runtime const RELA sections correctly")
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c12d9fa2afe7abcbe407a00e15719e1a1350c2a7 [1]
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Closes: https://lore.kernel.org/CA+G9fYvVktRhFtZXdNgVOL8j+ArsJDpvMLgCitaQvQmCx=hwOQ@mail.gmail.com/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
Cc: Ard Biesheuvel <ardb@kernel.org>
---
 scripts/Makefile.vmlinux | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index a62639982be5..c02f85c2e241 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -83,6 +83,9 @@ endif
 
 remove-section-y                                   := .modinfo
 remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) += '.rel*' '!.rel*.dyn'
+# for compatibility with binutils < 2.32
+# https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c12d9fa2afe7abcbe407a00e15719e1a1350c2a7
+remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) += '.rel.*'
 
 remove-symbols := -w --strip-symbol='__mod_device_table__*'
 

-- 
2.51.0
Re: [PATCH 2/3] kbuild: Add '.rel.*' strip pattern for vmlinux
Posted by Ard Biesheuvel 2 months, 1 week ago
On Wed, 8 Oct 2025 at 15:47, Nathan Chancellor <nathan@kernel.org> wrote:
>
> Prior to binutils commit c12d9fa2afe ("Support objcopy
> --remove-section=.relaFOO") [1] in 2.32, stripping relocation sections
> required the trailing period (i.e., '.rel.*') to work properly.
>
> After commit 3e86e4d74c04 ("kbuild: keep .modinfo section in
> vmlinux.unstripped"), there is an error with binutils 2.31.1 or earlier
> because these sections are not properly removed:
>
>   s390-linux-objcopy: st6tO8Ev: symbol `.modinfo' required but not present
>   s390-linux-objcopy:st6tO8Ev: no symbols
>
> Add the old pattern to resolve this issue (along with a comment to allow
> cleaning this when binutils 2.32 or newer is the minimum supported
> version). While the aforementioned kbuild change exposes this, the
> pattern was originally changed by commit 71d815bf5dfd ("kbuild: Strip
> runtime const RELA sections correctly"), where it would still be
> incorrect with binutils older than 2.32.
>
> Fixes: 71d815bf5dfd ("kbuild: Strip runtime const RELA sections correctly")
> Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c12d9fa2afe7abcbe407a00e15719e1a1350c2a7 [1]
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Closes: https://lore.kernel.org/CA+G9fYvVktRhFtZXdNgVOL8j+ArsJDpvMLgCitaQvQmCx=hwOQ@mail.gmail.com/
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

> ---
> Cc: Ard Biesheuvel <ardb@kernel.org>
> ---
>  scripts/Makefile.vmlinux | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
> index a62639982be5..c02f85c2e241 100644
> --- a/scripts/Makefile.vmlinux
> +++ b/scripts/Makefile.vmlinux
> @@ -83,6 +83,9 @@ endif
>
>  remove-section-y                                   := .modinfo
>  remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) += '.rel*' '!.rel*.dyn'
> +# for compatibility with binutils < 2.32
> +# https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=c12d9fa2afe7abcbe407a00e15719e1a1350c2a7
> +remove-section-$(CONFIG_ARCH_VMLINUX_NEEDS_RELOCS) += '.rel.*'
>
>  remove-symbols := -w --strip-symbol='__mod_device_table__*'
>
>
> --
> 2.51.0
>