On Fri, Oct 28, 2022 at 01:28:39AM +0900, Masahiro Yamada wrote:
> Jiri Slaby reported that building the kernel with AR=gcc-ar shows:
> /usr/bin/ar terminated with signal 13 [Broken pipe]
>
> Nathan Chancellor reported the latest AR=llvm-ar shows
> error: write on a pipe with no reader
>
> The latter occurs since LLVM commit 51b557adc131 ("Add an error message
> to the default SIGPIPE handler").
>
> The resulting vmlinux is correct, but it is better to silence it.
>
> 'head -n1' exits after reading the first line, so the pipe is closed.
>
> Use 'sed -n 1p' to eat the stream till the end.
>
> Fixes: 321648455061 ("kbuild: use obj-y instead extra-y for objects placed at the head")
> Link: https://github.com/ClangBuiltLinux/linux/issues/1651
> Reported-by: Jiri Slaby <jirislaby@xxxxxxxxxx>
> Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
> Tested-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> ---
>
> Changes in v2:
> - Update commit description to mention llvm-ar
>
> Makefile | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index e90bb2b38607..e9e7eff906a5 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1218,7 +1218,7 @@ quiet_cmd_ar_vmlinux.a = AR $@
> cmd_ar_vmlinux.a = \
> rm -f $@; \
> $(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
> - $(AR) mPiT $$($(AR) t $@ | head -n1) $@ $$($(AR) t $@ | grep -F -f $(srctree)/scripts/head-object-list.txt)
> + $(AR) mPiT $$($(AR) t $@ | sed -n 1p) $@ $$($(AR) t $@ | grep -F -f $(srctree)/scripts/head-object-list.txt)
>
> targets += vmlinux.a
> vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt autoksyms_recursive FORCE
> --
> 2.34.1
>
