From: Masahiro Yamada <masahiroy@kernel.org>
Date: Thu, 27 Oct 2022 16:28:39 +0000 (+0900)
Subject: kbuild: fix SIGPIPE error message for AR=gcc-ar and AR=llvm-ar
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=fb3041d61f68;p=linux.git

kbuild: fix SIGPIPE error message for AR=gcc-ar and AR=llvm-ar

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@kernel.org>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
---

diff --git a/Makefile b/Makefile
index e90bb2b38607a..e9e7eff906a5e 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