On Thu, Jan 05, 2023 at 12:13:06PM +0900, Masahiro Yamada wrote:
> Nathan Chancellor reports that the s390 vmlinux fails to link with
> GNU ld < 2.36 since commit 99cb0d917ffa ("arch: fix broken BuildID
> for arm64 and riscv").
>
> It happens for defconfig, or more specifically for CONFIG_EXPOLINE=y.
>
> $ s390x-linux-gnu-ld --version | head -n1
> GNU ld (GNU Binutils for Debian) 2.35.2
> $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- allnoconfig
> $ ./scripts/config -e CONFIG_EXPOLINE
> $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- olddefconfig
> $ make -s ARCH=s390 CROSS_COMPILE=s390x-linux-gnu-
> `.exit.text' referenced in section `.s390_return_reg' of drivers/base/dd.o: defined in discarded section `.exit.text' of drivers/base/dd.o
> make[1]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 1
> make: *** [Makefile:1252: vmlinux] Error 2
>
> arch/s390/kernel/vmlinux.lds.S wants to keep EXIT_TEXT:
>
> .exit.text : {
> EXIT_TEXT
> }
>
> But, at the same time, EXIT_TEXT is thrown away by DISCARD because
> s390 does not define RUNTIME_DISCARD_EXIT.
>
> I still do not understand why the latter wins after 99cb0d917ffa,
> but defining RUNTIME_DISCARD_EXIT seems correct because the comment
> line in arch/s390/kernel/vmlinux.lds.S says:
>
> /*
> * .exit.text is discarded at runtime, not link time,
> * to deal with references from __bug_table
> */
>
> Nathan also found that binutils commit 21401fc7bf67 ("Duplicate output
> sections in scripts") cured this issue, so we cannot reproduce it with
> binutils 2.36+, but it is better to not rely on it.
>
> Fixes: 99cb0d917ffa ("arch: fix broken BuildID for arm64 and riscv")
> Link: https://lore.kernel.org/all/Y7Jal56f6UBh1abE@dev-arch.thelio-3990X/
> Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> ---
>
> arch/s390/kernel/vmlinux.lds.S | 2 ++
> 1 file changed, 2 insertions(+)
Applied, thanks!
