From 2a0098d70640dda192a79966c14d449e7a34d675 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 15 Jan 2018 08:17:07 -0600 Subject: [PATCH] objtool: Fix seg fault with gold linker Objtool segfaults when the gold linker is used with CONFIG_MODVERSIONS=y and CONFIG_UNWINDER_ORC=y. With CONFIG_MODVERSIONS=y, the .o file gets passed to the linker before being passed to objtool. The gold linker seems to strip unused ELF symbols by default, which confuses objtool and causes the seg fault when it's trying to generate ORC metadata. Objtool should really be running immediately after GCC anyway, without a linker call in between. Change the makefile ordering so that objtool is called before the linker. Reported-and-tested-by: Markus Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: ee9f8fce9964 ("x86/unwind: Add the ORC unwinder") Link: http://lkml.kernel.org/r/355f04da33581f4a3bf82e5b512973624a1e23a2.1516025651.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- scripts/Makefile.build | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index e63af4e19382..6bed45dc2cb1 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -270,12 +270,18 @@ else objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable) endif +ifdef CONFIG_MODVERSIONS +objtool_o = $(@D)/.tmp_$(@F) +else +objtool_o = $(@) +endif + # 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory # 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file # '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_obj) $(objtool_args) "$(objtool_o)";) objtool_obj = $(if $(patsubst y%,, \ $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \ $(__objtool_obj)) @@ -291,15 +297,15 @@ objtool_dep = $(objtool_obj) \ define rule_cc_o_c $(call echo-cmd,checksrc) $(cmd_checksrc) \ $(call cmd_and_fixdep,cc_o_c) \ - $(cmd_modversions_c) \ $(call echo-cmd,objtool) $(cmd_objtool) \ + $(cmd_modversions_c) \ $(call echo-cmd,record_mcount) $(cmd_record_mcount) endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) \ - $(cmd_modversions_S) \ - $(call echo-cmd,objtool) $(cmd_objtool) + $(call echo-cmd,objtool) $(cmd_objtool) \ + $(cmd_modversions_S) endef # List module undefined symbols (or empty line if not enabled)