objtool: Fix seg fault with gold linker (2a0098d7) · Commits · 戴 / test

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 <M4rkusXXL@web.de> Signed-off-by:

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

Ingo Molnar <mingo@kernel.org>

scripts/Makefile.build

+10 −4

Original line number	Diff line number	Diff line
		@@ -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)

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