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Commit 2a0098d7 authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Ingo Molnar
Browse files

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: default avatarMarkus <M4rkusXXL@web.de>
Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: ee9f8fce ("x86/unwind: Add the ORC unwinder")
Link: http://lkml.kernel.org/r/355f04da33581f4a3bf82e5b512973624a1e23a2.1516025651.git.jpoimboe@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 28d437d5

scripts/Makefile.build

+10 −4
Original line number Original line Diff line number Diff line
@@ -270,12 +270,18 @@ else 
objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)

objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)

endif

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 := 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 := 'y': skip objtool checking for a file

# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file

# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file

cmd_objtool = $(if $(patsubst y%,, \

cmd_objtool = $(if $(patsubst y%,, \

	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \

	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \

	$(__objtool_obj) $(objtool_args) "$(@)";)

	$(__objtool_obj) $(objtool_args) "$(objtool_o)";)

objtool_obj = $(if $(patsubst y%,, \

objtool_obj = $(if $(patsubst y%,, \

	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \

	$(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n), \

	$(__objtool_obj))

	$(__objtool_obj))
@@ -291,15 +297,15 @@ objtool_dep = $(objtool_obj) \ 
define rule_cc_o_c

define rule_cc_o_c

	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \

	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \

	$(call cmd_and_fixdep,cc_o_c)					  \

	$(call cmd_and_fixdep,cc_o_c)					  \

	$(cmd_modversions_c)						  \

	$(call echo-cmd,objtool) $(cmd_objtool)				  \

	$(call echo-cmd,objtool) $(cmd_objtool)				  \

	$(cmd_modversions_c)						  \

	$(call echo-cmd,record_mcount) $(cmd_record_mcount)

	$(call echo-cmd,record_mcount) $(cmd_record_mcount)

endef

endef





define rule_as_o_S

define rule_as_o_S

	$(call cmd_and_fixdep,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

endef





# List module undefined symbols (or empty line if not enabled)

# List module undefined symbols (or empty line if not enabled)