Nathan Chancellor reported a kernel build error on Fedora 39:
$ clang --version | head -1
clang version 16.0.5 (Fedora 16.0.5-1.fc39)
$ s390x-linux-gnu-ld --version | head -1
GNU ld version 2.40-1.fc39
$ make -skj"$(nproc)" ARCH=s390 CC=clang CROSS_COMPILE=s390x-linux-gnu- olddefconfig all
s390x-linux-gnu-ld: arch/s390/boot/startup.o(.text+0x5b4): misaligned symbol `_decompressor_end' (0x35b0f) for relocation R_390_PC32DBL
make[3]: *** [.../arch/s390/boot/Makefile:78: arch/s390/boot/vmlinux] Error 1
It turned out that the problem with misaligned symbols on s390 was fixed
with commit 80ddf5ce1c92 ("s390: always build relocatable kernel") for the
kernel image, but did not take into account that the decompressor uses its
own set of CFLAGS, which come without -fPIE.
Add the -fPIE flag also to the decompresser CFLAGS to fix this.
Reported-by: Nathan Chancellor <[email protected]>
Suggested-by: Ulrich Weigand <[email protected]>
Link: https://github.com/ClangBuiltLinux/linux/issues/1747
Signed-off-by: Heiko Carstens <[email protected]>
---
arch/s390/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index ed646c583e4f..5ed242897b0d 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -27,6 +27,7 @@ KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float -mbac
KBUILD_CFLAGS_DECOMPRESSOR += -fno-asynchronous-unwind-tables
KBUILD_CFLAGS_DECOMPRESSOR += -ffreestanding
KBUILD_CFLAGS_DECOMPRESSOR += -fno-stack-protector
+KBUILD_CFLAGS_DECOMPRESSOR += -fPIE
KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-member)
KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g)
KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,))
--
2.39.2
On Thu, Jun 22, 2023 at 02:55:08PM +0200, Heiko Carstens wrote:
> Nathan Chancellor reported a kernel build error on Fedora 39:
>
> $ clang --version | head -1
> clang version 16.0.5 (Fedora 16.0.5-1.fc39)
>
> $ s390x-linux-gnu-ld --version | head -1
> GNU ld version 2.40-1.fc39
>
> $ make -skj"$(nproc)" ARCH=s390 CC=clang CROSS_COMPILE=s390x-linux-gnu- olddefconfig all
> s390x-linux-gnu-ld: arch/s390/boot/startup.o(.text+0x5b4): misaligned symbol `_decompressor_end' (0x35b0f) for relocation R_390_PC32DBL
> make[3]: *** [.../arch/s390/boot/Makefile:78: arch/s390/boot/vmlinux] Error 1
>
> It turned out that the problem with misaligned symbols on s390 was fixed
> with commit 80ddf5ce1c92 ("s390: always build relocatable kernel") for the
> kernel image, but did not take into account that the decompressor uses its
> own set of CFLAGS, which come without -fPIE.
>
> Add the -fPIE flag also to the decompresser CFLAGS to fix this.
>
I think this should also have:
Reported-by: CKI <[email protected]>
Link: https://lore.kernel.org/[email protected]/
I technically just forwarded the report and did a little extra testing.
> Reported-by: Nathan Chancellor <[email protected]>
> Suggested-by: Ulrich Weigand <[email protected]>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1747
> Signed-off-by: Heiko Carstens <[email protected]>
Thanks for the quick patch, this fixes the error and I did a simple boot
test in QEMU with the resulting kernel, which showed no issues.
Tested-by: Nathan Chancellor <[email protected]>
> ---
> arch/s390/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/s390/Makefile b/arch/s390/Makefile
> index ed646c583e4f..5ed242897b0d 100644
> --- a/arch/s390/Makefile
> +++ b/arch/s390/Makefile
> @@ -27,6 +27,7 @@ KBUILD_CFLAGS_DECOMPRESSOR += -fno-delete-null-pointer-checks -msoft-float -mbac
> KBUILD_CFLAGS_DECOMPRESSOR += -fno-asynchronous-unwind-tables
> KBUILD_CFLAGS_DECOMPRESSOR += -ffreestanding
> KBUILD_CFLAGS_DECOMPRESSOR += -fno-stack-protector
> +KBUILD_CFLAGS_DECOMPRESSOR += -fPIE
> KBUILD_CFLAGS_DECOMPRESSOR += $(call cc-disable-warning, address-of-packed-member)
> KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO),-g)
> KBUILD_CFLAGS_DECOMPRESSOR += $(if $(CONFIG_DEBUG_INFO_DWARF4), $(call cc-option, -gdwarf-4,))
> --
> 2.39.2
>
On Thu, Jun 22, 2023 at 02:35:38PM +0000, Nathan Chancellor wrote:
> On Thu, Jun 22, 2023 at 02:55:08PM +0200, Heiko Carstens wrote:
> > Nathan Chancellor reported a kernel build error on Fedora 39:
> >
> > $ clang --version | head -1
> > clang version 16.0.5 (Fedora 16.0.5-1.fc39)
> >
> > $ s390x-linux-gnu-ld --version | head -1
> > GNU ld version 2.40-1.fc39
> >
> > $ make -skj"$(nproc)" ARCH=s390 CC=clang CROSS_COMPILE=s390x-linux-gnu- olddefconfig all
> > s390x-linux-gnu-ld: arch/s390/boot/startup.o(.text+0x5b4): misaligned symbol `_decompressor_end' (0x35b0f) for relocation R_390_PC32DBL
> > make[3]: *** [.../arch/s390/boot/Makefile:78: arch/s390/boot/vmlinux] Error 1
> >
> > It turned out that the problem with misaligned symbols on s390 was fixed
> > with commit 80ddf5ce1c92 ("s390: always build relocatable kernel") for the
> > kernel image, but did not take into account that the decompressor uses its
> > own set of CFLAGS, which come without -fPIE.
> >
> > Add the -fPIE flag also to the decompresser CFLAGS to fix this.
> >
>
> I think this should also have:
>
> Reported-by: CKI <[email protected]>
> Link: https://lore.kernel.org/[email protected]/
>
> I technically just forwarded the report and did a little extra testing.
Ok, added.
> Thanks for the quick patch, this fixes the error and I did a simple boot
> test in QEMU with the resulting kernel, which showed no issues.
>
> Tested-by: Nathan Chancellor <[email protected]>
And this as well. :) Thanks a lot!