RE: [PATCH] objtool: Don't use -Werror

[David Laight <David.Laight@ACULAB.COM>]

From: Josh Poimboeuf
> Sent: 05 April 2019 18:23
> On Fri, Apr 05, 2019 at 05:17:15PM +0000, David Laight wrote:
> > > Hm, I don't see that in cmd_objtool, or any commits from you in
> > > scripts/Makefile.build.
> >
> > Not sure I remember actually committing them.
> > Maybe 'git diff' isn't doing what I expect :-)
> > I hate git.
> 
> Do you see it here?
> 
>   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/Makefile.build

No, I must have had to tell git to apply the change locally.
I can't see how to get git to diff against the 'real' head.
Anyway a 'random' number of ^ after HEAD gave me:

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index e7889f4..a2f7abe 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -193,7 +193,9 @@ else
 cmd_cc_o_c = $(CC) $(c_flags) -c -o $(@D)/.tmp_$(@F) $<

 cmd_modversions_c =                                                            \
-       if $(OBJDUMP) -h $(@D)/.tmp_$(@F) | grep -q __ksymtab; then             \
+       if ! obj_headers=$$($(OBJDUMP) -h $(@D)/.tmp_$(@F)); then               \
+               false;                                                          \
+       elif echo "$$obj_headers" | grep -q __ksymtab; then                     \
                $(call cmd_gensymtypes_c,$(KBUILD_SYMTYPES),$(@:.o=.symtypes))  \
                    > $(@D)/.tmp_$(@F:.o=.ver);                                 \
                                                                                \
@@ -277,7 +279,14 @@ endif
 # 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file
 cmd_objtool = $(if $(patsubst y%,, \
        $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
-       $(__objtool_obj) $(objtool_args) "$(objtool_o)";)
+       $(__objtool_obj) $(objtool_args) "$(objtool_o)" && { \
+               $(OBJDUMP) -h "$(objtool_o)" >/dev/null 2>&1 || { \
+                       echo >&2 "******* objtool generated the invalid file $(objtool_o)"; \
+                       echo >&2 "******* Update libelf.so or disable the ORC unwinder"; \
+                       /bin/false; \
+               }; \
+       };)
+
 objtool_obj = $(if $(patsubst y%,, \
        $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \
        $(__objtool_obj))

Do you want a formal patch?

	David

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