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From:   Samuel Holland <samuel@sholland.org>
To:     Masahiro Yamada <masahiroy@kernel.org>,
        linux-kbuild@vger.kernel.org
Cc:     Samuel Holland <samuel@sholland.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        linux-kernel@vger.kernel.org
Subject: [PATCH] kbuild: Fix running modpost with musl libc
Date:   Tue, 27 Dec 2022 15:48:21 -0600
Message-Id: <20221227214821.16495-1-samuel@sholland.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

commit 3d57e1b7b1d4 ("kbuild: refactor the prerequisites of the modpost
rule") moved 'vmlinux.o' inside modpost-args, possibly before some of
the other options. However, getopt() in musl libc follows POSIX and
stops looking for options upon reaching the first non-option argument.
As a result, the '-T' option is misinterpreted as a positional argument,
and the build fails:

  make -f ./scripts/Makefile.modpost
     scripts/mod/modpost   -E   -o Module.symvers vmlinux.o -T modules.order
  -T: No such file or directory
  make[1]: *** [scripts/Makefile.modpost:137: Module.symvers] Error 1
  make: *** [Makefile:1960: modpost] Error 2

The fix is to move all options before 'vmlinux.o' in modpost-args.

Fixes: 3d57e1b7b1d4 ("kbuild: refactor the prerequisites of the modpost rule")
Signed-off-by: Samuel Holland <samuel@sholland.org>
---

 scripts/Makefile.modpost | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 5eb5e8280379..0ee296cf520c 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -55,6 +55,17 @@ ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
 modpost-args += -n
 endif
 
+ifneq ($(KBUILD_MODPOST_WARN)$(missing-input),)
+modpost-args += -w
+endif
+
+# Read out modules.order to pass in modpost.
+# Otherwise, allmodconfig would fail with "Argument list too long".
+ifdef KBUILD_MODULES
+modpost-args += -T $(MODORDER)
+modpost-deps += $(MODORDER)
+endif
+
 ifeq ($(KBUILD_EXTMOD),)
 
 # Generate the list of in-tree objects in vmlinux
@@ -113,17 +124,6 @@ modpost-args += -e $(addprefix -i , $(KBUILD_EXTRA_SYMBOLS))
 
 endif # ($(KBUILD_EXTMOD),)
 
-ifneq ($(KBUILD_MODPOST_WARN)$(missing-input),)
-modpost-args += -w
-endif
-
-ifdef KBUILD_MODULES
-modpost-args += -T $(MODORDER)
-modpost-deps += $(MODORDER)
-endif
-
-# Read out modules.order to pass in modpost.
-# Otherwise, allmodconfig would fail with "Argument list too long".
 quiet_cmd_modpost = MODPOST $@
       cmd_modpost = \
 	$(if $(missing-input), \
-- 
2.37.4