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* [PATCH 0/3] kbuild: remove many tool coverage variables
@ 2024-05-06 13:35 Masahiro Yamada
  2024-05-06 13:35 ` [PATCH 1/3] kbuild: provide reasonable defaults for tool coverage Masahiro Yamada
                   ` (3 more replies)
  0 siblings, 4 replies; 10+ messages in thread
From: Masahiro Yamada @ 2024-05-06 13:35 UTC (permalink / raw)
  To: linux-kbuild; +Cc: linux-arch, linux-kernel, Masahiro Yamada


This patch set removes many instances of the following variables:

  - OBJECT_FILES_NON_STANDARD
  - KASAN_SANITIZE
  - UBSAN_SANITIZE
  - KCSAN_SANITIZE
  - KMSAN_SANITIZE
  - GCOV_PROFILE
  - KCOV_INSTRUMENT

Such tools are intended only for kernel space objects, most of which
are listed in obj-y, lib-y, or obj-m.

The best guess is, objects in $(obj-y), $(lib-y), $(obj-m) can opt in
such tools. Otherwise, not.

This works in most places.



Masahiro Yamada (3):
  kbuild: provide reasonable defaults for tool coverage
  Makefile: remove redundant tool coverage variables
  kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in
    scripts/Makefile.modfinal

 arch/arm/boot/bootp/Makefile           |  1 -
 arch/arm/boot/compressed/Makefile      |  7 -------
 arch/arm/vdso/Makefile                 |  9 ---------
 arch/arm64/kernel/pi/Makefile          |  6 ------
 arch/arm64/kernel/vdso/Makefile        |  8 --------
 arch/arm64/kvm/hyp/nvhe/Makefile       | 13 -------------
 arch/csky/kernel/vdso/Makefile         |  4 ----
 arch/loongarch/vdso/Makefile           |  7 -------
 arch/mips/boot/compressed/Makefile     |  6 ------
 arch/mips/vdso/Makefile                |  7 -------
 arch/parisc/boot/compressed/Makefile   |  4 ----
 arch/powerpc/kernel/vdso/Makefile      |  8 --------
 arch/powerpc/purgatory/Makefile        |  3 ---
 arch/riscv/boot/Makefile               |  2 --
 arch/riscv/kernel/compat_vdso/Makefile |  6 ------
 arch/riscv/kernel/pi/Makefile          |  6 ------
 arch/riscv/kernel/vdso/Makefile        |  6 ------
 arch/riscv/purgatory/Makefile          |  8 --------
 arch/s390/boot/Makefile                |  2 ++
 arch/s390/kernel/vdso32/Makefile       |  8 --------
 arch/s390/kernel/vdso64/Makefile       |  8 --------
 arch/s390/purgatory/Makefile           |  8 --------
 arch/sh/boot/compressed/Makefile       |  3 ---
 arch/sparc/vdso/Makefile               |  2 --
 arch/x86/boot/Makefile                 | 15 ---------------
 arch/x86/boot/compressed/Makefile      | 11 -----------
 arch/x86/entry/vdso/Makefile           | 26 --------------------------
 arch/x86/purgatory/Makefile            |  9 ---------
 arch/x86/realmode/rm/Makefile          | 11 -----------
 arch/x86/um/vdso/Makefile              |  7 -------
 arch/xtensa/boot/lib/Makefile          |  5 -----
 drivers/firmware/efi/libstub/Makefile  | 11 -----------
 drivers/misc/lkdtm/Makefile            |  4 ----
 init/Makefile                          |  3 ---
 scripts/Makefile.build                 |  2 +-
 scripts/Makefile.lib                   | 20 ++++++++++++--------
 scripts/Makefile.modfinal              |  4 +++-
 scripts/Makefile.vmlinux               |  3 ---
 scripts/mod/Makefile                   |  1 -
 39 files changed, 18 insertions(+), 256 deletions(-)

-- 
2.40.1


^ permalink raw reply	[flat|nested] 10+ messages in thread
* [PATCH 1/3] kbuild: provide reasonable defaults for tool coverage
  2024-05-06 13:35 [PATCH 0/3] kbuild: remove many tool coverage variables Masahiro Yamada
@ 2024-05-06 13:35 ` Masahiro Yamada
  2024-05-06 13:35 ` [PATCH 2/3] Makefile: remove redundant tool coverage variables Masahiro Yamada
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 10+ messages in thread
From: Masahiro Yamada @ 2024-05-06 13:35 UTC (permalink / raw)
  To: linux-kbuild; +Cc: linux-arch, linux-kernel, Masahiro Yamada

The objtool, sanitizers (KASAN, UBSAN, etc.), and profilers (GCOV, etc.)
are intended for kernel space objects. To exclude objects from their
coverage, you need to set variables such as OBJECT_FILES_NON_STNDARD=y,
KASAN_SANITIZE=n, etc.

For instance, the following are not kernel objects, and therefore should
opt out of coverage:

  - vDSO
  - purgatory
  - bootloader (arch/*/boot/)

Kbuild can detect these cases without relying on such variables because
objects not directly linked to vmlinux or modules are considered
"non-standard objects".

Detecting objects linked to vmlinux or modules is straightforward:

  - objects added to obj-y are linked to vmlinux
  - objects added to lib-y are linked to vmlinux
  - objects added to obj-m are linked to modules

In the past, there was yet another case:

  - object paths added to head-y were linked to vmlinux

Commit ce697ccee1a8 ("kbuild: remove head-y syntax") eliminated this.

There are still some exceptions. For example, arch/s390/boot/Makefile
needlessly uses obj-y for the bootloader objects, which can be fixed
later.

Going forward, objects that are not listed in obj-y, lib-y, or obj-m
will opt out of objtool, sanitizers, and profilers by default.

You can still override the Kbuild decision by explicitly specifying
OBJECT_FILES_NON_STANDARD, KASAN_SANITIZE, etc. but most of such Make
variables can be removed.

The next commit will clean up redundant variables.

Note:

The coverage for some objects will be changed:

  - exclude .vmlinux.export.o from UBSAN, KCOV
  - exclude arch/csky/kernel/vdso/vgettimeofday.o from UBSAN
  - exclude arch/parisc/kernel/vdso32/vdso32.so from UBSAN
  - exclude arch/parisc/kernel/vdso64/vdso64.so from UBSAN
  - exclude arch/x86/um/vdso/um_vdso.o from UBSAN
  - exclude drivers/misc/lkdtm/rodata.o from UBSAN, KCOV
  - exclude init/version-timestamp.o from UBSAN, KCOV
  - exclude lib/test_fortify/*.o from all santizers and profilers

I believe these are positive effects.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 scripts/Makefile.build |  2 +-
 scripts/Makefile.lib   | 20 ++++++++++++--------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index c9c07a6144eb..56bacd992a09 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -214,7 +214,7 @@ endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
 # '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
 
-is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),y)
+is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(target-stem).o)$(OBJECT_FILES_NON_STANDARD)n),$(is-kernel-object))
 
 $(obj)/%.o: private objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))
 
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 5972ec4ee29b..d3180182af47 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -154,7 +154,7 @@ _cpp_flags     = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(target-stem).lds)
 #
 ifeq ($(CONFIG_GCOV_KERNEL),y)
 _c_flags += $(if $(patsubst n%,, \
-		$(GCOV_PROFILE_$(target-stem).o)$(GCOV_PROFILE)$(CONFIG_GCOV_PROFILE_ALL)), \
+		$(GCOV_PROFILE_$(target-stem).o)$(GCOV_PROFILE)$(if $(is-kernel-object),$(CONFIG_GCOV_PROFILE_ALL))), \
 		$(CFLAGS_GCOV))
 endif
 
@@ -165,32 +165,32 @@ endif
 ifeq ($(CONFIG_KASAN),y)
 ifneq ($(CONFIG_KASAN_HW_TAGS),y)
 _c_flags += $(if $(patsubst n%,, \
-		$(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)y), \
+		$(KASAN_SANITIZE_$(target-stem).o)$(KASAN_SANITIZE)$(is-kernel-object)), \
 		$(CFLAGS_KASAN), $(CFLAGS_KASAN_NOSANITIZE))
 endif
 endif
 
 ifeq ($(CONFIG_KMSAN),y)
 _c_flags += $(if $(patsubst n%,, \
-		$(KMSAN_SANITIZE_$(target-stem).o)$(KMSAN_SANITIZE)y), \
+		$(KMSAN_SANITIZE_$(target-stem).o)$(KMSAN_SANITIZE)$(is-kernel-object)), \
 		$(CFLAGS_KMSAN))
 _c_flags += $(if $(patsubst n%,, \
-		$(KMSAN_ENABLE_CHECKS_$(target-stem).o)$(KMSAN_ENABLE_CHECKS)y), \
+		$(KMSAN_ENABLE_CHECKS_$(target-stem).o)$(KMSAN_ENABLE_CHECKS)$(is-kernel-object)), \
 		, -mllvm -msan-disable-checks=1)
 endif
 
 ifeq ($(CONFIG_UBSAN),y)
 _c_flags += $(if $(patsubst n%,, \
-		$(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_SANITIZE)y), \
+		$(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_SANITIZE)$(is-kernel-object)), \
 		$(CFLAGS_UBSAN))
 _c_flags += $(if $(patsubst n%,, \
-		$(UBSAN_SIGNED_WRAP_$(target-stem).o)$(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_SIGNED_WRAP)$(UBSAN_SANITIZE)y), \
+		$(UBSAN_SIGNED_WRAP_$(target-stem).o)$(UBSAN_SANITIZE_$(target-stem).o)$(UBSAN_SIGNED_WRAP)$(UBSAN_SANITIZE)$(is-kernel-object)), \
 		$(CFLAGS_UBSAN_SIGNED_WRAP))
 endif
 
 ifeq ($(CONFIG_KCOV),y)
 _c_flags += $(if $(patsubst n%,, \
-	$(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(CONFIG_KCOV_INSTRUMENT_ALL)), \
+	$(KCOV_INSTRUMENT_$(target-stem).o)$(KCOV_INSTRUMENT)$(if $(is-kernel-object),$(CONFIG_KCOV_INSTRUMENT_ALL))), \
 	$(CFLAGS_KCOV))
 endif
 
@@ -200,7 +200,7 @@ endif
 #
 ifeq ($(CONFIG_KCSAN),y)
 _c_flags += $(if $(patsubst n%,, \
-	$(KCSAN_SANITIZE_$(target-stem).o)$(KCSAN_SANITIZE)y), \
+	$(KCSAN_SANITIZE_$(target-stem).o)$(KCSAN_SANITIZE)$(is-kernel-object)), \
 	$(CFLAGS_KCSAN))
 # Some uninstrumented files provide implied barriers required to avoid false
 # positives: set KCSAN_INSTRUMENT_BARRIERS for barrier instrumentation only.
@@ -219,6 +219,10 @@ _cpp_flags += $(addprefix -I, $(src) $(obj))
 endif
 endif
 
+# If $(is-kernel-object) is 'y', this object will be linked to vmlinux or modules
+is-kernel-object = $(or $(part-of-builtin),$(part-of-module))
+
+part-of-builtin = $(if $(filter $(basename $@).o, $(real-obj-y) $(lib-y)),y)
 part-of-module = $(if $(filter $(basename $@).o, $(real-obj-m)),y)
 quiet_modtag = $(if $(part-of-module),[M],   )
 
-- 
2.40.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH 2/3] Makefile: remove redundant tool coverage variables
  2024-05-06 13:35 [PATCH 0/3] kbuild: remove many tool coverage variables Masahiro Yamada
  2024-05-06 13:35 ` [PATCH 1/3] kbuild: provide reasonable defaults for tool coverage Masahiro Yamada
@ 2024-05-06 13:35 ` Masahiro Yamada
  2024-05-06 13:35 ` [PATCH 3/3] kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in scripts/Makefile.modfinal Masahiro Yamada
  2024-05-13 18:48 ` [PATCH 0/3] kbuild: remove many tool coverage variables Kees Cook
  3 siblings, 0 replies; 10+ messages in thread
From: Masahiro Yamada @ 2024-05-06 13:35 UTC (permalink / raw)
  To: linux-kbuild; +Cc: linux-arch, linux-kernel, Masahiro Yamada

Now Kbuild provides reasonable defaults for objtool, sanitizers, and
profilers.

Remove redundant variables.

Note:

The coverage for some objects will be changed:

  - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
  - include arch/sparc/vdso/vdso-image-*.o into UBSAN
  - include arch/sparc/vdso/vma.o into UBSAN
  - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
  - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
  - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
  - include arch/x86/entry/vdso/vma.o into GCOV, KCOV
  - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV

I believe these are positive effects because all of them are kernel
space objects.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 arch/arm/boot/bootp/Makefile           |  1 -
 arch/arm/boot/compressed/Makefile      |  7 -------
 arch/arm/vdso/Makefile                 |  9 ---------
 arch/arm64/kernel/pi/Makefile          |  6 ------
 arch/arm64/kernel/vdso/Makefile        |  8 --------
 arch/arm64/kvm/hyp/nvhe/Makefile       | 13 -------------
 arch/csky/kernel/vdso/Makefile         |  4 ----
 arch/loongarch/vdso/Makefile           |  7 -------
 arch/mips/boot/compressed/Makefile     |  6 ------
 arch/mips/vdso/Makefile                |  7 -------
 arch/parisc/boot/compressed/Makefile   |  4 ----
 arch/powerpc/kernel/vdso/Makefile      |  8 --------
 arch/powerpc/purgatory/Makefile        |  3 ---
 arch/riscv/boot/Makefile               |  2 --
 arch/riscv/kernel/compat_vdso/Makefile |  6 ------
 arch/riscv/kernel/pi/Makefile          |  6 ------
 arch/riscv/kernel/vdso/Makefile        |  6 ------
 arch/riscv/purgatory/Makefile          |  8 --------
 arch/s390/boot/Makefile                |  2 ++
 arch/s390/kernel/vdso32/Makefile       |  8 --------
 arch/s390/kernel/vdso64/Makefile       |  8 --------
 arch/s390/purgatory/Makefile           |  8 --------
 arch/sh/boot/compressed/Makefile       |  3 ---
 arch/sparc/vdso/Makefile               |  2 --
 arch/x86/boot/Makefile                 | 15 ---------------
 arch/x86/boot/compressed/Makefile      | 11 -----------
 arch/x86/entry/vdso/Makefile           | 26 --------------------------
 arch/x86/purgatory/Makefile            |  9 ---------
 arch/x86/realmode/rm/Makefile          | 11 -----------
 arch/x86/um/vdso/Makefile              |  7 -------
 arch/xtensa/boot/lib/Makefile          |  5 -----
 drivers/firmware/efi/libstub/Makefile  | 11 -----------
 drivers/misc/lkdtm/Makefile            |  4 ----
 init/Makefile                          |  3 ---
 scripts/Makefile.vmlinux               |  3 ---
 scripts/mod/Makefile                   |  1 -
 36 files changed, 2 insertions(+), 246 deletions(-)

diff --git a/arch/arm/boot/bootp/Makefile b/arch/arm/boot/bootp/Makefile
index a2934e6fd89a..f3443f7d7b02 100644
--- a/arch/arm/boot/bootp/Makefile
+++ b/arch/arm/boot/bootp/Makefile
@@ -5,7 +5,6 @@
 # This file is included by the global makefile so that you can add your own
 # architecture-specific flags and dependencies.
 #
-GCOV_PROFILE	:= n
 
 ifdef PHYS_OFFSET
 add_hex = $(shell printf 0x%x $$(( $(1) + $(2) )) )
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 726ecabcef09..6bca03c0c7f0 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -22,13 +22,6 @@ ifeq ($(CONFIG_ARM_VIRT_EXT),y)
 OBJS		+= hyp-stub.o
 endif
 
-GCOV_PROFILE		:= n
-KASAN_SANITIZE		:= n
-
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT		:= n
-UBSAN_SANITIZE		:= n
-
 #
 # Architecture dependencies
 #
diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile
index d761bd2e2f40..01067a2bc43b 100644
--- a/arch/arm/vdso/Makefile
+++ b/arch/arm/vdso/Makefile
@@ -33,15 +33,6 @@ else
 CFLAGS_vgettimeofday.o = -O2 -include $(c-gettimeofday-y)
 endif
 
-# Disable gcov profiling for VDSO code
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT := n
-
-KASAN_SANITIZE := n
-
 # Force dependency
 $(obj)/vdso.o : $(obj)/vdso.so
 
diff --git a/arch/arm64/kernel/pi/Makefile b/arch/arm64/kernel/pi/Makefile
index 4393b41f0b71..4d11a8c29181 100644
--- a/arch/arm64/kernel/pi/Makefile
+++ b/arch/arm64/kernel/pi/Makefile
@@ -19,12 +19,6 @@ KBUILD_CFLAGS	:= $(filter-out $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
 # disable LTO
 KBUILD_CFLAGS	:= $(filter-out $(CC_FLAGS_LTO), $(KBUILD_CFLAGS))
 
-GCOV_PROFILE	:= n
-KASAN_SANITIZE	:= n
-KCSAN_SANITIZE	:= n
-UBSAN_SANITIZE	:= n
-KCOV_INSTRUMENT	:= n
-
 hostprogs	:= relacheck
 
 quiet_cmd_piobjcopy = $(quiet_cmd_objcopy)
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index 53e86d3bc159..d63930c82839 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -40,11 +40,6 @@ CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
 				$(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
 				$(CC_FLAGS_LTO) $(CC_FLAGS_CFI) \
 				-Wmissing-prototypes -Wmissing-declarations
-KASAN_SANITIZE			:= n
-KCSAN_SANITIZE			:= n
-UBSAN_SANITIZE			:= n
-OBJECT_FILES_NON_STANDARD	:= y
-KCOV_INSTRUMENT			:= n
 
 CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
 
@@ -52,9 +47,6 @@ ifneq ($(c-gettimeofday-y),)
   CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
 endif
 
-# Disable gcov profiling for VDSO code
-GCOV_PROFILE := n
-
 targets += vdso.lds
 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
 
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 2250253a6429..50fa0ffb6b7e 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -97,16 +97,3 @@ KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS) $(CC_FLAGS_CFI)
 # causes a build failure. Remove profile optimization flags.
 KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%, $(KBUILD_CFLAGS))
 KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -fno-unwind-tables
-
-# KVM nVHE code is run at a different exception code with a different map, so
-# compiler instrumentation that inserts callbacks or checks into the code may
-# cause crashes. Just disable it.
-GCOV_PROFILE	:= n
-KASAN_SANITIZE	:= n
-KCSAN_SANITIZE	:= n
-UBSAN_SANITIZE	:= n
-KCOV_INSTRUMENT	:= n
-
-# Skip objtool checking for this directory because nVHE code is compiled with
-# non-standard build rules.
-OBJECT_FILES_NON_STANDARD := y
diff --git a/arch/csky/kernel/vdso/Makefile b/arch/csky/kernel/vdso/Makefile
index e79a725f5075..bc2261f5a8d4 100644
--- a/arch/csky/kernel/vdso/Makefile
+++ b/arch/csky/kernel/vdso/Makefile
@@ -23,10 +23,6 @@ obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
 obj-y += vdso.o vdso-syms.o
 CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
 
-# Disable gcov profiling for VDSO code
-GCOV_PROFILE := n
-KCOV_INSTRUMENT := n
-
 # Force dependency
 $(obj)/vdso.o: $(obj)/vdso.so
 
diff --git a/arch/loongarch/vdso/Makefile b/arch/loongarch/vdso/Makefile
index cdfc4c793e2c..d724d46b07c8 100644
--- a/arch/loongarch/vdso/Makefile
+++ b/arch/loongarch/vdso/Makefile
@@ -1,11 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 # Objects to go into the VDSO.
 
-KASAN_SANITIZE := n
-UBSAN_SANITIZE := n
-KCOV_INSTRUMENT := n
-OBJECT_FILES_NON_STANDARD := y
-
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile
 
@@ -39,8 +34,6 @@ ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
 	$(filter -E%,$(KBUILD_CFLAGS)) -nostdlib -shared \
 	--hash-style=sysv --build-id -T
 
-GCOV_PROFILE := n
-
 #
 # Shared build commands.
 #
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index 6cc28173bee8..e0b8ec9a9516 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -34,12 +34,6 @@ KBUILD_AFLAGS := $(KBUILD_AFLAGS) -D__ASSEMBLY__ \
 	-DBOOT_HEAP_SIZE=$(BOOT_HEAP_SIZE) \
 	-DKERNEL_ENTRY=$(VMLINUX_ENTRY_ADDRESS)
 
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT		:= n
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-KCSAN_SANITIZE			:= n
-
 # decompressor objects (linked with vmlinuz)
 vmlinuzobjs-y := $(obj)/head.o $(obj)/decompress.o $(obj)/string.o $(obj)/bswapsi.o
 
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index 40b839e91806..b289b2c1b294 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -1,9 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 # Objects to go into the VDSO.
 
-# Sanitizer runtimes are unavailable and cannot be linked here.
- KCSAN_SANITIZE			:= n
-
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile
 
@@ -60,10 +57,6 @@ ldflags-y := -Bsymbolic --no-undefined -soname=linux-vdso.so.1 \
 
 CFLAGS_REMOVE_vdso.o = $(CC_FLAGS_FTRACE)
 
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-KCOV_INSTRUMENT := n
-
 # Check that we don't have PIC 'jalr t9' calls left
 quiet_cmd_vdso_mips_check = VDSOCHK $@
       cmd_vdso_mips_check = if $(OBJDUMP) --disassemble $@ | grep -E -h "jalr.*t9" > /dev/null; \
diff --git a/arch/parisc/boot/compressed/Makefile b/arch/parisc/boot/compressed/Makefile
index a294a1b58ee7..92227fa813dc 100644
--- a/arch/parisc/boot/compressed/Makefile
+++ b/arch/parisc/boot/compressed/Makefile
@@ -5,10 +5,6 @@
 # create a compressed self-extracting vmlinux image from the original vmlinux
 #
 
-KCOV_INSTRUMENT := n
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-
 OBJECTS := head.o real2.o firmware.o misc.o piggy.o
 targets := vmlinux.lds vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2
 targets += vmlinux.bin.xz vmlinux.bin.lzma vmlinux.bin.lzo vmlinux.bin.lz4
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 7d66b6e07993..1425b6edc66b 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -47,12 +47,6 @@ obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
 targets += $(obj-vdso64) vdso64.so.dbg vgettimeofday-64.o
 obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
 
-GCOV_PROFILE := n
-KCOV_INSTRUMENT := n
-UBSAN_SANITIZE := n
-KASAN_SANITIZE := n
-KCSAN_SANITIZE := n
-
 ccflags-y := -fno-common -fno-builtin
 ldflags-y := -Wl,--hash-style=both -nostdlib -shared -z noexecstack $(CLANG_FLAGS)
 ldflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
@@ -114,5 +108,3 @@ quiet_cmd_vdso64ld_and_check = VDSO64L $@
       cmd_vdso64ld_and_check = $(VDSOCC) $(ldflags-y) $(LD64FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^); $(cmd_vdso_check)
 quiet_cmd_vdso64as = VDSO64A $@
       cmd_vdso64as = $(VDSOCC) $(a_flags) $(AS64FLAGS) -c -o $@ $<
-
-OBJECT_FILES_NON_STANDARD := y
diff --git a/arch/powerpc/purgatory/Makefile b/arch/powerpc/purgatory/Makefile
index 78473d69cd2b..e9890085953e 100644
--- a/arch/powerpc/purgatory/Makefile
+++ b/arch/powerpc/purgatory/Makefile
@@ -1,8 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 
-KASAN_SANITIZE := n
-KCSAN_SANITIZE := n
-
 targets += trampoline_$(BITS).o purgatory.ro
 
 # When profile-guided optimization is enabled, llvm emits two different
diff --git a/arch/riscv/boot/Makefile b/arch/riscv/boot/Makefile
index 8e7fc0edf21d..869c0345b908 100644
--- a/arch/riscv/boot/Makefile
+++ b/arch/riscv/boot/Makefile
@@ -14,8 +14,6 @@
 # Based on the ia64 and arm64 boot/Makefile.
 #
 
-KCOV_INSTRUMENT := n
-
 OBJCOPYFLAGS_Image :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
 OBJCOPYFLAGS_loader.bin :=-O binary
 OBJCOPYFLAGS_xipImage :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
diff --git a/arch/riscv/kernel/compat_vdso/Makefile b/arch/riscv/kernel/compat_vdso/Makefile
index 362208dfa7ee..24e37d1ef7ec 100644
--- a/arch/riscv/kernel/compat_vdso/Makefile
+++ b/arch/riscv/kernel/compat_vdso/Makefile
@@ -34,12 +34,6 @@ obj-compat_vdso := $(addprefix $(obj)/, $(obj-compat_vdso))
 obj-y += compat_vdso.o
 CPPFLAGS_compat_vdso.lds += -P -C -DCOMPAT_VDSO -U$(ARCH)
 
-# Disable profiling and instrumentation for VDSO code
-GCOV_PROFILE := n
-KCOV_INSTRUMENT := n
-KASAN_SANITIZE := n
-UBSAN_SANITIZE := n
-
 # Force dependency
 $(obj)/compat_vdso.o: $(obj)/compat_vdso.so
 
diff --git a/arch/riscv/kernel/pi/Makefile b/arch/riscv/kernel/pi/Makefile
index b75f150b923d..50bc5ef7dd2f 100644
--- a/arch/riscv/kernel/pi/Makefile
+++ b/arch/riscv/kernel/pi/Makefile
@@ -17,12 +17,6 @@ KBUILD_CFLAGS	+= -mcmodel=medany
 CFLAGS_cmdline_early.o += -D__NO_FORTIFY
 CFLAGS_lib-fdt_ro.o += -D__NO_FORTIFY
 
-GCOV_PROFILE	:= n
-KASAN_SANITIZE	:= n
-KCSAN_SANITIZE	:= n
-UBSAN_SANITIZE	:= n
-KCOV_INSTRUMENT	:= n
-
 $(obj)/%.pi.o: OBJCOPYFLAGS := --prefix-symbols=__pi_ \
 			       --remove-section=.note.gnu.property \
 			       --prefix-alloc-sections=.init.pi
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 25f0ee629971..f7ef8ad9b550 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -39,12 +39,6 @@ endif
 CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS)
 CFLAGS_REMOVE_hwprobe.o = $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS)
 
-# Disable profiling and instrumentation for VDSO code
-GCOV_PROFILE := n
-KCOV_INSTRUMENT := n
-KASAN_SANITIZE := n
-UBSAN_SANITIZE := n
-
 # Force dependency
 $(obj)/vdso.o: $(obj)/vdso.so
 
diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile
index 280b0eb352b8..f11945ee2490 100644
--- a/arch/riscv/purgatory/Makefile
+++ b/arch/riscv/purgatory/Makefile
@@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-OBJECT_FILES_NON_STANDARD := y
 
 purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o memcpy.o memset.o
 purgatory-y += strcmp.o strlen.o strncmp.o
@@ -47,13 +46,6 @@ LDFLAGS_purgatory.ro := -r $(PURGATORY_LDFLAGS)
 LDFLAGS_purgatory.chk := $(PURGATORY_LDFLAGS)
 targets += purgatory.ro purgatory.chk
 
-# Sanitizer, etc. runtimes are unavailable and cannot be linked here.
-GCOV_PROFILE	:= n
-KASAN_SANITIZE	:= n
-UBSAN_SANITIZE	:= n
-KCSAN_SANITIZE	:= n
-KCOV_INSTRUMENT := n
-
 # These are adjustments to the compiler flags used for objects that
 # make up the standalone purgatory.ro
 
diff --git a/arch/s390/boot/Makefile b/arch/s390/boot/Makefile
index 294f08a8811a..5a10c4fa4b24 100644
--- a/arch/s390/boot/Makefile
+++ b/arch/s390/boot/Makefile
@@ -3,6 +3,8 @@
 # Makefile for the linux s390-specific parts of the memory manager.
 #
 
+# These must be disabled explicitly because this Makefile uses obj-y
+# for bootloader objects.
 KCOV_INSTRUMENT := n
 GCOV_PROFILE := n
 UBSAN_SANITIZE := n
diff --git a/arch/s390/kernel/vdso32/Makefile b/arch/s390/kernel/vdso32/Makefile
index c263b91adfb1..df928fee26b5 100644
--- a/arch/s390/kernel/vdso32/Makefile
+++ b/arch/s390/kernel/vdso32/Makefile
@@ -1,8 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 # List of files in the vdso
 
-KCOV_INSTRUMENT := n
-
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile
 obj-vdso32 = vdso_user_wrapper-32.o note-32.o
@@ -32,12 +30,6 @@ obj-y += vdso32_wrapper.o
 targets += vdso32.lds
 CPPFLAGS_vdso32.lds += -P -C -U$(ARCH)
 
-# Disable gcov profiling, ubsan and kasan for VDSO code
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-KASAN_SANITIZE := n
-KCSAN_SANITIZE := n
-
 # Force dependency (incbin is bad)
 $(obj)/vdso32_wrapper.o : $(obj)/vdso32.so
 
diff --git a/arch/s390/kernel/vdso64/Makefile b/arch/s390/kernel/vdso64/Makefile
index 9566bed7d5b2..6da1b9ad8ab0 100644
--- a/arch/s390/kernel/vdso64/Makefile
+++ b/arch/s390/kernel/vdso64/Makefile
@@ -1,8 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 # List of files in the vdso
 
-KCOV_INSTRUMENT := n
-
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile
 obj-vdso64 = vdso_user_wrapper.o note.o
@@ -37,12 +35,6 @@ obj-y += vdso64_wrapper.o
 targets += vdso64.lds
 CPPFLAGS_vdso64.lds += -P -C -U$(ARCH)
 
-# Disable gcov profiling, ubsan and kasan for VDSO code
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-KASAN_SANITIZE := n
-KCSAN_SANITIZE := n
-
 # Force dependency (incbin is bad)
 $(obj)/vdso64_wrapper.o : $(obj)/vdso64.so
 
diff --git a/arch/s390/purgatory/Makefile b/arch/s390/purgatory/Makefile
index 4e930f566878..24eccaa29337 100644
--- a/arch/s390/purgatory/Makefile
+++ b/arch/s390/purgatory/Makefile
@@ -1,7 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 
-OBJECT_FILES_NON_STANDARD := y
-
 purgatory-y := head.o purgatory.o string.o sha256.o mem.o
 
 targets += $(purgatory-y) purgatory.lds purgatory purgatory.chk purgatory.ro
@@ -15,12 +13,6 @@ CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY
 $(obj)/mem.o: $(srctree)/arch/s390/lib/mem.S FORCE
 	$(call if_changed_rule,as_o_S)
 
-KCOV_INSTRUMENT := n
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-KASAN_SANITIZE := n
-KCSAN_SANITIZE := n
-
 KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes
 KBUILD_CFLAGS += -Wno-pointer-sign -Wno-sign-compare
 KBUILD_CFLAGS += -fno-zero-initialized-in-bss -fno-builtin -ffreestanding
diff --git a/arch/sh/boot/compressed/Makefile b/arch/sh/boot/compressed/Makefile
index 6c6c791a1d06..3a46b871463d 100644
--- a/arch/sh/boot/compressed/Makefile
+++ b/arch/sh/boot/compressed/Makefile
@@ -11,9 +11,6 @@ OBJECTS := head_32.o misc.o cache.o piggy.o \
 targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 \
            vmlinux.bin.lzma vmlinux.bin.xz vmlinux.bin.lzo $(OBJECTS)
 
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
-
 #
 # IMAGE_OFFSET is the load offset of the compression loader
 #
diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile
index 0fe134abbcf1..243dbfc4609d 100644
--- a/arch/sparc/vdso/Makefile
+++ b/arch/sparc/vdso/Makefile
@@ -2,7 +2,6 @@
 #
 # Building vDSO images for sparc.
 #
-UBSAN_SANITIZE := n
 
 # files to link into the vdso
 vobjs-y := vdso-note.o vclock_gettime.o
@@ -106,4 +105,3 @@ quiet_cmd_vdso = VDSO    $@
 		sh $(src)/checkundef.sh '$(OBJDUMP)' '$@'
 
 VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 -Bsymbolic
-GCOV_PROFILE := n
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 29cda98c65f8..1cf24ff6acac 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -9,19 +9,6 @@
 # Changed by many, many contributors over the years.
 #
 
-# Sanitizer runtimes are unavailable and cannot be linked for early boot code.
-KASAN_SANITIZE			:= n
-KCSAN_SANITIZE			:= n
-KMSAN_SANITIZE			:= n
-OBJECT_FILES_NON_STANDARD	:= y
-
-# Kernel does not boot with kcov instrumentation here.
-# One of the problems observed was insertion of __sanitizer_cov_trace_pc()
-# callback into middle of per-cpu data enabling code. Thus the callback observed
-# inconsistent state and crashed. We are interested mostly in syscall coverage,
-# so boot code is not interesting anyway.
-KCOV_INSTRUMENT		:= n
-
 # If you want to preset the SVGA mode, uncomment the next line and
 # set SVGA_MODE to whatever number you want.
 # Set it to -DSVGA_MODE=NORMAL_VGA if you just want the EGA/VGA mode.
@@ -69,8 +56,6 @@ KBUILD_CFLAGS	:= $(REALMODE_CFLAGS) -D_SETUP
 KBUILD_AFLAGS	:= $(KBUILD_CFLAGS) -D__ASSEMBLY__
 KBUILD_CFLAGS	+= $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
 KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
 
 $(obj)/bzImage: asflags-y  := $(SVGA_MODE)
 
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index e9522c6893be..243ee86cb1b1 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -17,15 +17,6 @@
 #	(see scripts/Makefile.lib size_append)
 #	compressed vmlinux.bin.all + u32 size of vmlinux.bin.all
 
-# Sanitizer runtimes are unavailable and cannot be linked for early boot code.
-KASAN_SANITIZE			:= n
-KCSAN_SANITIZE			:= n
-KMSAN_SANITIZE			:= n
-OBJECT_FILES_NON_STANDARD	:= y
-
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT		:= n
-
 targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
 	vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4 vmlinux.bin.zst
 
@@ -59,8 +50,6 @@ KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h
 CFLAGS_sev.o += -I$(objtree)/arch/x86/lib/
 
 KBUILD_AFLAGS  := $(KBUILD_CFLAGS) -D__ASSEMBLY__
-GCOV_PROFILE := n
-UBSAN_SANITIZE :=n
 
 KBUILD_LDFLAGS := -m elf_$(UTS_MACHINE)
 KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info)
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index c003452dba8c..215a1b202a91 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -6,20 +6,6 @@
 # Include the generic Makefile to check the built vDSO:
 include $(srctree)/lib/vdso/Makefile
 
-# Sanitizer runtimes are unavailable and cannot be linked here.
-KASAN_SANITIZE			:= n
-KMSAN_SANITIZE_vclock_gettime.o := n
-KMSAN_SANITIZE_vdso32/vclock_gettime.o	:= n
-KMSAN_SANITIZE_vgetcpu.o	:= n
-KMSAN_SANITIZE_vdso32/vgetcpu.o	:= n
-
-UBSAN_SANITIZE			:= n
-KCSAN_SANITIZE			:= n
-OBJECT_FILES_NON_STANDARD	:= y
-
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT		:= n
-
 # Files to link into the vDSO:
 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
 vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
@@ -28,23 +14,12 @@ vobjs-$(CONFIG_X86_SGX)	+= vsgx.o
 
 # Files to link into the kernel:
 obj-y						+= vma.o extable.o
-KASAN_SANITIZE_vma.o				:= y
-UBSAN_SANITIZE_vma.o				:= y
-KCSAN_SANITIZE_vma.o				:= y
-
-OBJECT_FILES_NON_STANDARD_vma.o			:= n
-OBJECT_FILES_NON_STANDARD_extable.o		:= n
 
 # vDSO images to build:
 obj-$(CONFIG_X86_64)				+= vdso-image-64.o
 obj-$(CONFIG_X86_X32_ABI)			+= vdso-image-x32.o
 obj-$(CONFIG_COMPAT_32)				+= vdso-image-32.o vdso32-setup.o
 
-OBJECT_FILES_NON_STANDARD_vdso-image-32.o	:= n
-OBJECT_FILES_NON_STANDARD_vdso-image-x32.o	:= n
-OBJECT_FILES_NON_STANDARD_vdso-image-64.o	:= n
-OBJECT_FILES_NON_STANDARD_vdso32-setup.o	:= n
-
 vobjs := $(addprefix $(obj)/, $(vobjs-y))
 vobjs32 := $(addprefix $(obj)/, $(vobjs32-y))
 
@@ -180,7 +155,6 @@ quiet_cmd_vdso = VDSO    $@
 
 VDSO_LDFLAGS = -shared --hash-style=both --build-id=sha1 \
 	$(call ld-option, --eh-frame-hdr) -Bsymbolic -z noexecstack
-GCOV_PROFILE := n
 
 quiet_cmd_vdso_and_check = VDSO    $@
       cmd_vdso_and_check = $(cmd_vdso); $(cmd_vdso_check)
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index bc31863c5ee6..0a16f1373cf5 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-OBJECT_FILES_NON_STANDARD := y
 
 purgatory-y := purgatory.o stack.o setup-x86_$(BITS).o sha256.o entry64.o string.o
 
@@ -30,14 +29,6 @@ LDFLAGS_purgatory.ro := -r $(PURGATORY_LDFLAGS)
 LDFLAGS_purgatory.chk := $(PURGATORY_LDFLAGS)
 targets += purgatory.ro purgatory.chk
 
-# Sanitizer, etc. runtimes are unavailable and cannot be linked here.
-GCOV_PROFILE	:= n
-KASAN_SANITIZE	:= n
-UBSAN_SANITIZE	:= n
-KCSAN_SANITIZE	:= n
-KMSAN_SANITIZE	:= n
-KCOV_INSTRUMENT := n
-
 # These are adjustments to the compiler flags used for objects that
 # make up the standalone purgatory.ro
 
diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile
index f614009d3e4e..a0fb39abc5c8 100644
--- a/arch/x86/realmode/rm/Makefile
+++ b/arch/x86/realmode/rm/Makefile
@@ -7,15 +7,6 @@
 #
 #
 
-# Sanitizer runtimes are unavailable and cannot be linked here.
-KASAN_SANITIZE			:= n
-KCSAN_SANITIZE			:= n
-KMSAN_SANITIZE			:= n
-OBJECT_FILES_NON_STANDARD	:= y
-
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT		:= n
-
 always-y := realmode.bin realmode.relocs
 
 wakeup-objs	:= wakeup_asm.o wakemain.o video-mode.o
@@ -76,5 +67,3 @@ KBUILD_CFLAGS	:= $(REALMODE_CFLAGS) -D_SETUP -D_WAKEUP \
 		   -I$(srctree)/arch/x86/boot
 KBUILD_AFLAGS	:= $(KBUILD_CFLAGS) -D__ASSEMBLY__
 KBUILD_CFLAGS	+= -fno-asynchronous-unwind-tables
-GCOV_PROFILE := n
-UBSAN_SANITIZE := n
diff --git a/arch/x86/um/vdso/Makefile b/arch/x86/um/vdso/Makefile
index 2303fa59971c..6a77ea6434ff 100644
--- a/arch/x86/um/vdso/Makefile
+++ b/arch/x86/um/vdso/Makefile
@@ -3,12 +3,6 @@
 # Building vDSO images for x86.
 #
 
-# do not instrument on vdso because KASAN is not compatible with user mode
-KASAN_SANITIZE			:= n
-
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT                := n
-
 VDSO64-y		:= y
 
 vdso-install-$(VDSO64-y)	+= vdso.so
@@ -66,4 +60,3 @@ quiet_cmd_vdso = VDSO    $@
 		 sh $(src)/checkundef.sh '$(NM)' '$@'
 
 VDSO_LDFLAGS = -fPIC -shared -Wl,--hash-style=sysv -z noexecstack
-GCOV_PROFILE := n
diff --git a/arch/xtensa/boot/lib/Makefile b/arch/xtensa/boot/lib/Makefile
index 0378a22a08e3..39e1ef0f9d15 100644
--- a/arch/xtensa/boot/lib/Makefile
+++ b/arch/xtensa/boot/lib/Makefile
@@ -15,11 +15,6 @@ CFLAGS_REMOVE_inftrees.o = -pg
 CFLAGS_REMOVE_inffast.o = -pg
 endif
 
-KASAN_SANITIZE := n
-KCSAN_SANITIZE := n
-KCOV_INSTRUMENT := n
-GCOV_PROFILE := n
-
 CFLAGS_REMOVE_inflate.o += -fstack-protector -fstack-protector-strong
 CFLAGS_REMOVE_zmem.o += -fstack-protector -fstack-protector-strong
 CFLAGS_REMOVE_inftrees.o += -fstack-protector -fstack-protector-strong
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 31eb1e287ce1..06f0428a723c 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -56,17 +56,6 @@ KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_CFI), $(KBUILD_CFLAGS))
 # disable LTO
 KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO), $(KBUILD_CFLAGS))
 
-GCOV_PROFILE			:= n
-# Sanitizer runtimes are unavailable and cannot be linked here.
-KASAN_SANITIZE			:= n
-KCSAN_SANITIZE			:= n
-KMSAN_SANITIZE			:= n
-UBSAN_SANITIZE			:= n
-OBJECT_FILES_NON_STANDARD	:= y
-
-# Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
-KCOV_INSTRUMENT			:= n
-
 lib-y				:= efi-stub-helper.o gop.o secureboot.o tpm.o \
 				   file.o mem.o random.o randomalloc.o pci.o \
 				   skip_spaces.o lib-cmdline.o lib-ctype.o \
diff --git a/drivers/misc/lkdtm/Makefile b/drivers/misc/lkdtm/Makefile
index 95ef971b5e1c..33fe61152a15 100644
--- a/drivers/misc/lkdtm/Makefile
+++ b/drivers/misc/lkdtm/Makefile
@@ -15,10 +15,6 @@ lkdtm-$(CONFIG_PPC_64S_HASH_MMU)	+= powerpc.o
 
 KASAN_SANITIZE_stackleak.o	:= n
 
-KASAN_SANITIZE_rodata.o			:= n
-KCSAN_SANITIZE_rodata.o			:= n
-KCOV_INSTRUMENT_rodata.o		:= n
-OBJECT_FILES_NON_STANDARD_rodata.o	:= y
 CFLAGS_REMOVE_rodata.o			+= $(CC_FLAGS_LTO) $(RETHUNK_CFLAGS)
 
 OBJCOPYFLAGS :=
diff --git a/init/Makefile b/init/Makefile
index 3c48d97538c1..ab71cedc5fd6 100644
--- a/init/Makefile
+++ b/init/Makefile
@@ -59,6 +59,3 @@ include/generated/utsversion.h: FORCE
 
 $(obj)/version-timestamp.o: include/generated/utsversion.h
 CFLAGS_version-timestamp.o := -include include/generated/utsversion.h
-KASAN_SANITIZE_version-timestamp.o := n
-KCSAN_SANITIZE_version-timestamp.o := n
-GCOV_PROFILE_version-timestamp.o := n
diff --git a/scripts/Makefile.vmlinux b/scripts/Makefile.vmlinux
index c9f3e03124d7..49946cb96844 100644
--- a/scripts/Makefile.vmlinux
+++ b/scripts/Makefile.vmlinux
@@ -18,9 +18,6 @@ quiet_cmd_cc_o_c = CC      $@
 	$(call if_changed_dep,cc_o_c)
 
 ifdef CONFIG_MODULES
-KASAN_SANITIZE_.vmlinux.export.o := n
-KCSAN_SANITIZE_.vmlinux.export.o := n
-GCOV_PROFILE_.vmlinux.export.o := n
 targets += .vmlinux.export.o
 vmlinux: .vmlinux.export.o
 endif
diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
index 3c54125eb373..c729bc936bae 100644
--- a/scripts/mod/Makefile
+++ b/scripts/mod/Makefile
@@ -1,5 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-OBJECT_FILES_NON_STANDARD := y
 CFLAGS_REMOVE_empty.o += $(CC_FLAGS_LTO)
 
 hostprogs-always-y	+= modpost mk_elfconfig
-- 
2.40.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* [PATCH 3/3] kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in scripts/Makefile.modfinal
  2024-05-06 13:35 [PATCH 0/3] kbuild: remove many tool coverage variables Masahiro Yamada
  2024-05-06 13:35 ` [PATCH 1/3] kbuild: provide reasonable defaults for tool coverage Masahiro Yamada
  2024-05-06 13:35 ` [PATCH 2/3] Makefile: remove redundant tool coverage variables Masahiro Yamada
@ 2024-05-06 13:35 ` Masahiro Yamada
  2024-05-13 18:48 ` [PATCH 0/3] kbuild: remove many tool coverage variables Kees Cook
  3 siblings, 0 replies; 10+ messages in thread
From: Masahiro Yamada @ 2024-05-06 13:35 UTC (permalink / raw)
  To: linux-kbuild; +Cc: linux-arch, linux-kernel, Masahiro Yamada

Instead of filtering out the GCOV and KCSAN flags, let's set GCOV_PROFILE
and KCSAN_SANITIZE to 'n', as in other Makefiles.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 scripts/Makefile.modfinal | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 79fcf2731686..3bec9043e4f3 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -21,9 +21,11 @@ __modfinal: $(modules:%.o=%.ko)
 # modname and part-of-module are set to make c_flags define proper module flags
 modname = $(notdir $(@:.mod.o=))
 part-of-module = y
+GCOV_PROFILE := n
+KCSAN_SANITIZE := n
 
 quiet_cmd_cc_o_c = CC [M]  $@
-      cmd_cc_o_c = $(CC) $(filter-out $(CC_FLAGS_CFI) $(CFLAGS_GCOV) $(CFLAGS_KCSAN), $(c_flags)) -c -o $@ $<
+      cmd_cc_o_c = $(CC) $(filter-out $(CC_FLAGS_CFI), $(c_flags)) -c -o $@ $<
 
 %.mod.o: %.mod.c FORCE
 	$(call if_changed_dep,cc_o_c)
-- 
2.40.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/3] kbuild: remove many tool coverage variables
  2024-05-06 13:35 [PATCH 0/3] kbuild: remove many tool coverage variables Masahiro Yamada
                   ` (2 preceding siblings ...)
  2024-05-06 13:35 ` [PATCH 3/3] kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in scripts/Makefile.modfinal Masahiro Yamada
@ 2024-05-13 18:48 ` Kees Cook
  2024-05-13 19:54   ` Marco Elver
                     ` (2 more replies)
  3 siblings, 3 replies; 10+ messages in thread
From: Kees Cook @ 2024-05-13 18:48 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: linux-kbuild, linux-arch, linux-kernel, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Marco Elver, Josh Poimboeuf, Peter Zijlstra,
	Peter Oberparleiter, Roberto Sassu, Johannes Berg, kasan-dev,
	linux-hardening

In the future can you CC the various maintainers of the affected
tooling? :)

On Mon, May 06, 2024 at 10:35:41PM +0900, Masahiro Yamada wrote:
> 
> This patch set removes many instances of the following variables:
> 
>   - OBJECT_FILES_NON_STANDARD
>   - KASAN_SANITIZE
>   - UBSAN_SANITIZE
>   - KCSAN_SANITIZE
>   - KMSAN_SANITIZE
>   - GCOV_PROFILE
>   - KCOV_INSTRUMENT
> 
> Such tools are intended only for kernel space objects, most of which
> are listed in obj-y, lib-y, or obj-m.

This is a reasonable assertion, and the changes really simplify things
now and into the future. Thanks for finding such a clean solution! I
note that it also immediately fixes the issue noticed and fixed here:
https://lore.kernel.org/all/20240513122754.1282833-1-roberto.sassu@huaweicloud.com/

> The best guess is, objects in $(obj-y), $(lib-y), $(obj-m) can opt in
> such tools. Otherwise, not.
> 
> This works in most places.

I am worried about the use of "guess" and "most", though. :) Before, we
had some clear opt-out situations, and now it's more of a side-effect. I
think this is okay, but I'd really like to know more about your testing.

It seems like you did build testing comparing build flags, since you
call out some of the explicit changes in patch 2, quoting:

>  - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
>  - include arch/sparc/vdso/vdso-image-*.o into UBSAN
>  - include arch/sparc/vdso/vma.o into UBSAN
>  - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
>  - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
>  - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
>  - include arch/x86/entry/vdso/vma.o into GCOV, KCOV
>  - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV

I would agree that these cases are all likely desirable.

Did you find any cases where you found that instrumentation was _removed_
where not expected?

-Kees

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/3] kbuild: remove many tool coverage variables
  2024-05-13 18:48 ` [PATCH 0/3] kbuild: remove many tool coverage variables Kees Cook
@ 2024-05-13 19:54   ` Marco Elver
  2024-05-13 22:50     ` Masahiro Yamada
  2024-05-13 22:39   ` Masahiro Yamada
  2024-05-14  7:31   ` Roberto Sassu
  2 siblings, 1 reply; 10+ messages in thread
From: Marco Elver @ 2024-05-13 19:54 UTC (permalink / raw)
  To: Kees Cook
  Cc: Masahiro Yamada, linux-kbuild, linux-arch, linux-kernel,
	Andrey Ryabinin, Alexander Potapenko, Andrey Konovalov,
	Dmitry Vyukov, Vincenzo Frascino, Josh Poimboeuf, Peter Zijlstra,
	Peter Oberparleiter, Roberto Sassu, Johannes Berg, kasan-dev,
	linux-hardening

On Mon, 13 May 2024 at 20:48, Kees Cook <keescook@chromium.org> wrote:
>
> In the future can you CC the various maintainers of the affected
> tooling? :)
>
> On Mon, May 06, 2024 at 10:35:41PM +0900, Masahiro Yamada wrote:
> >
> > This patch set removes many instances of the following variables:
> >
> >   - OBJECT_FILES_NON_STANDARD
> >   - KASAN_SANITIZE
> >   - UBSAN_SANITIZE
> >   - KCSAN_SANITIZE
> >   - KMSAN_SANITIZE
> >   - GCOV_PROFILE
> >   - KCOV_INSTRUMENT
> >
> > Such tools are intended only for kernel space objects, most of which
> > are listed in obj-y, lib-y, or obj-m.

I welcome the simplification, but see below.

> This is a reasonable assertion, and the changes really simplify things
> now and into the future. Thanks for finding such a clean solution! I
> note that it also immediately fixes the issue noticed and fixed here:
> https://lore.kernel.org/all/20240513122754.1282833-1-roberto.sassu@huaweicloud.com/
>
> > The best guess is, objects in $(obj-y), $(lib-y), $(obj-m) can opt in
> > such tools. Otherwise, not.
> >
> > This works in most places.
>
> I am worried about the use of "guess" and "most", though. :) Before, we
> had some clear opt-out situations, and now it's more of a side-effect. I
> think this is okay, but I'd really like to know more about your testing.
>
> It seems like you did build testing comparing build flags, since you
> call out some of the explicit changes in patch 2, quoting:
>
> >  - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
> >  - include arch/sparc/vdso/vdso-image-*.o into UBSAN
> >  - include arch/sparc/vdso/vma.o into UBSAN
> >  - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vma.o into GCOV, KCOV
> >  - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV
>
> I would agree that these cases are all likely desirable.
>
> Did you find any cases where you found that instrumentation was _removed_
> where not expected?

In addition, did you boot test these kernels? While I currently don't
recall if the vdso code caused us problems (besides the linking
problem for non-kernel objects), anything that is opted out from
instrumentation in arch/ code needs to be carefully tested if it
should be opted back into instrumentation. We had many fun hours
debugging boot hangs or other recursion issues due to instrumented
arch code.

Thanks,
-- Marco

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/3] kbuild: remove many tool coverage variables
  2024-05-13 18:48 ` [PATCH 0/3] kbuild: remove many tool coverage variables Kees Cook
  2024-05-13 19:54   ` Marco Elver
@ 2024-05-13 22:39   ` Masahiro Yamada
  2024-05-13 23:28     ` Kees Cook
  2024-05-14  7:31   ` Roberto Sassu
  2 siblings, 1 reply; 10+ messages in thread
From: Masahiro Yamada @ 2024-05-13 22:39 UTC (permalink / raw)
  To: Kees Cook
  Cc: linux-kbuild, linux-arch, linux-kernel, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Marco Elver, Josh Poimboeuf, Peter Zijlstra,
	Peter Oberparleiter, Roberto Sassu, Johannes Berg, kasan-dev,
	linux-hardening

On Tue, May 14, 2024 at 3:48 AM Kees Cook <keescook@chromium.org> wrote:
>
> In the future can you CC the various maintainers of the affected
> tooling? :)


Sorry, I was too lazy to add CC for treewide changes like this.
Anyway, thanks for adding CC.




> On Mon, May 06, 2024 at 10:35:41PM +0900, Masahiro Yamada wrote:
> >
> > This patch set removes many instances of the following variables:
> >
> >   - OBJECT_FILES_NON_STANDARD
> >   - KASAN_SANITIZE
> >   - UBSAN_SANITIZE
> >   - KCSAN_SANITIZE
> >   - KMSAN_SANITIZE
> >   - GCOV_PROFILE
> >   - KCOV_INSTRUMENT
> >
> > Such tools are intended only for kernel space objects, most of which
> > are listed in obj-y, lib-y, or obj-m.
>
> This is a reasonable assertion, and the changes really simplify things
> now and into the future. Thanks for finding such a clean solution! I
> note that it also immediately fixes the issue noticed and fixed here:
> https://lore.kernel.org/all/20240513122754.1282833-1-roberto.sassu@huaweicloud.com/
>
> > The best guess is, objects in $(obj-y), $(lib-y), $(obj-m) can opt in
> > such tools. Otherwise, not.
> >
> > This works in most places.
>
> I am worried about the use of "guess" and "most", though. :) Before, we
> had some clear opt-out situations, and now it's more of a side-effect. I
> think this is okay, but I'd really like to know more about your testing.


- defconfig for arc, hexagon, loongarch, microblaze, sh, xtensa
- allmodconfig for the other architectures


(IIRC, allmodconfig failed for the first case, for reasons unrelated
to this patch set, so I used defconfig instead.
I do not remember what errors I observed)


I checked the diff of .*.cmd files.





>
> It seems like you did build testing comparing build flags, since you
> call out some of the explicit changes in patch 2, quoting:
>
> >  - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
> >  - include arch/sparc/vdso/vdso-image-*.o into UBSAN
> >  - include arch/sparc/vdso/vma.o into UBSAN
> >  - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vma.o into GCOV, KCOV
> >  - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV
>
> I would agree that these cases are all likely desirable.
>
> Did you find any cases where you found that instrumentation was _removed_
> where not expected?




See the commit log of 1/3.


> Note:
>
> The coverage for some objects will be changed:
>
>   - exclude .vmlinux.export.o from UBSAN, KCOV
>   - exclude arch/csky/kernel/vdso/vgettimeofday.o from UBSAN
>   - exclude arch/parisc/kernel/vdso32/vdso32.so from UBSAN
>   - exclude arch/parisc/kernel/vdso64/vdso64.so from UBSAN
>   - exclude arch/x86/um/vdso/um_vdso.o from UBSAN
>   - exclude drivers/misc/lkdtm/rodata.o from UBSAN, KCOV
>   - exclude init/version-timestamp.o from UBSAN, KCOV
>   - exclude lib/test_fortify/*.o from all santizers and profilers
>
> I believe these are positive effects.




-- 
Best Regards
Masahiro Yamada

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/3] kbuild: remove many tool coverage variables
  2024-05-13 19:54   ` Marco Elver
@ 2024-05-13 22:50     ` Masahiro Yamada
  0 siblings, 0 replies; 10+ messages in thread
From: Masahiro Yamada @ 2024-05-13 22:50 UTC (permalink / raw)
  To: Marco Elver
  Cc: Kees Cook, linux-kbuild, linux-arch, linux-kernel,
	Andrey Ryabinin, Alexander Potapenko, Andrey Konovalov,
	Dmitry Vyukov, Vincenzo Frascino, Josh Poimboeuf, Peter Zijlstra,
	Peter Oberparleiter, Roberto Sassu, Johannes Berg, kasan-dev,
	linux-hardening

On Tue, May 14, 2024 at 4:55 AM Marco Elver <elver@google.com> wrote:
>
> On Mon, 13 May 2024 at 20:48, Kees Cook <keescook@chromium.org> wrote:
> >
> > In the future can you CC the various maintainers of the affected
> > tooling? :)
> >
> > On Mon, May 06, 2024 at 10:35:41PM +0900, Masahiro Yamada wrote:
> > >
> > > This patch set removes many instances of the following variables:
> > >
> > >   - OBJECT_FILES_NON_STANDARD
> > >   - KASAN_SANITIZE
> > >   - UBSAN_SANITIZE
> > >   - KCSAN_SANITIZE
> > >   - KMSAN_SANITIZE
> > >   - GCOV_PROFILE
> > >   - KCOV_INSTRUMENT
> > >
> > > Such tools are intended only for kernel space objects, most of which
> > > are listed in obj-y, lib-y, or obj-m.
>
> I welcome the simplification, but see below.
>
> > This is a reasonable assertion, and the changes really simplify things
> > now and into the future. Thanks for finding such a clean solution! I
> > note that it also immediately fixes the issue noticed and fixed here:
> > https://lore.kernel.org/all/20240513122754.1282833-1-roberto.sassu@huaweicloud.com/
> >
> > > The best guess is, objects in $(obj-y), $(lib-y), $(obj-m) can opt in
> > > such tools. Otherwise, not.
> > >
> > > This works in most places.
> >
> > I am worried about the use of "guess" and "most", though. :) Before, we
> > had some clear opt-out situations, and now it's more of a side-effect. I
> > think this is okay, but I'd really like to know more about your testing.
> >
> > It seems like you did build testing comparing build flags, since you
> > call out some of the explicit changes in patch 2, quoting:
> >
> > >  - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
> > >  - include arch/sparc/vdso/vdso-image-*.o into UBSAN
> > >  - include arch/sparc/vdso/vma.o into UBSAN
> > >  - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> > >  - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> > >  - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> > >  - include arch/x86/entry/vdso/vma.o into GCOV, KCOV
> > >  - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV
> >
> > I would agree that these cases are all likely desirable.
> >
> > Did you find any cases where you found that instrumentation was _removed_
> > where not expected?
>
> In addition, did you boot test these kernels?


No. I didn't.




> While I currently don't
> recall if the vdso code caused us problems (besides the linking
> problem for non-kernel objects), anything that is opted out from
> instrumentation in arch/ code needs to be carefully tested if it
> should be opted back into instrumentation. We had many fun hours
> debugging boot hangs or other recursion issues due to instrumented
> arch code.


As I replied to Kees, I checked the diff of .*.cmd files.

I believe checking the compiler flags for every object
is comprehensive testing.

If the same set of compiler flags is passed,
the same build artifact is generated.



-- 
Best Regards
Masahiro Yamada

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/3] kbuild: remove many tool coverage variables
  2024-05-13 22:39   ` Masahiro Yamada
@ 2024-05-13 23:28     ` Kees Cook
  0 siblings, 0 replies; 10+ messages in thread
From: Kees Cook @ 2024-05-13 23:28 UTC (permalink / raw)
  To: Masahiro Yamada
  Cc: linux-kbuild, linux-arch, linux-kernel, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Marco Elver, Josh Poimboeuf, Peter Zijlstra,
	Peter Oberparleiter, Roberto Sassu, Johannes Berg, kasan-dev,
	linux-hardening

On Tue, May 14, 2024 at 07:39:31AM +0900, Masahiro Yamada wrote:
> On Tue, May 14, 2024 at 3:48 AM Kees Cook <keescook@chromium.org> wrote:
> > I am worried about the use of "guess" and "most", though. :) Before, we
> > had some clear opt-out situations, and now it's more of a side-effect. I
> > think this is okay, but I'd really like to know more about your testing.
> 
> - defconfig for arc, hexagon, loongarch, microblaze, sh, xtensa
> - allmodconfig for the other architectures
> 
> (IIRC, allmodconfig failed for the first case, for reasons unrelated
> to this patch set, so I used defconfig instead.
> I do not remember what errors I observed)
> 
> I checked the diff of .*.cmd files.

Ah-ha, perfect! Thanks. :)

> > Did you find any cases where you found that instrumentation was _removed_
> > where not expected?
> 
> See the commit log of 1/3.

Okay, thanks. I wasn't sure if that was the complete set or just part of
the "most" bit. :)

Thanks! I think this should all be fine. I'm not aware of anything
melting down yet from these changes being in -next, so:

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 10+ messages in thread
* Re: [PATCH 0/3] kbuild: remove many tool coverage variables
  2024-05-13 18:48 ` [PATCH 0/3] kbuild: remove many tool coverage variables Kees Cook
  2024-05-13 19:54   ` Marco Elver
  2024-05-13 22:39   ` Masahiro Yamada
@ 2024-05-14  7:31   ` Roberto Sassu
  2 siblings, 0 replies; 10+ messages in thread
From: Roberto Sassu @ 2024-05-14  7:31 UTC (permalink / raw)
  To: Kees Cook, Masahiro Yamada
  Cc: linux-kbuild, linux-arch, linux-kernel, Andrey Ryabinin,
	Alexander Potapenko, Andrey Konovalov, Dmitry Vyukov,
	Vincenzo Frascino, Marco Elver, Josh Poimboeuf, Peter Zijlstra,
	Peter Oberparleiter, Johannes Berg, kasan-dev, linux-hardening

On Mon, 2024-05-13 at 11:48 -0700, Kees Cook wrote:
> In the future can you CC the various maintainers of the affected
> tooling? :)
> 
> On Mon, May 06, 2024 at 10:35:41PM +0900, Masahiro Yamada wrote:
> > 
> > This patch set removes many instances of the following variables:
> > 
> >   - OBJECT_FILES_NON_STANDARD
> >   - KASAN_SANITIZE
> >   - UBSAN_SANITIZE
> >   - KCSAN_SANITIZE
> >   - KMSAN_SANITIZE
> >   - GCOV_PROFILE
> >   - KCOV_INSTRUMENT
> > 
> > Such tools are intended only for kernel space objects, most of which
> > are listed in obj-y, lib-y, or obj-m.
> 
> This is a reasonable assertion, and the changes really simplify things
> now and into the future. Thanks for finding such a clean solution! I
> note that it also immediately fixes the issue noticed and fixed here:
> https://lore.kernel.org/all/20240513122754.1282833-1-roberto.sassu@huaweicloud.com/

Yes, this patch set fixes the issue too.

Tested-by: Roberto Sassu <roberto.sassu@huawei.com>

Now UBSAN complains about misaligned address, such as:

[    0.150000][    T1] UBSAN: misaligned-access in kernel/workqueue.c:5514:3
[    0.150000][    T1] member access within misaligned address 0000000064c36f78 for type 'struct pool_workqueue'
[    0.150000][    T1] which requires 512 byte alignment
[    0.150000][    T1] CPU: 0 PID: 1 Comm: swapper Not tainted 6.9.0-dont-use-00003-g3b621c71dc5e #2244

But I guess this is for a separate thread.

Thanks

Roberto

> > The best guess is, objects in $(obj-y), $(lib-y), $(obj-m) can opt in
> > such tools. Otherwise, not.
> > 
> > This works in most places.
> 
> I am worried about the use of "guess" and "most", though. :) Before, we
> had some clear opt-out situations, and now it's more of a side-effect. I
> think this is okay, but I'd really like to know more about your testing.
> 
> It seems like you did build testing comparing build flags, since you
> call out some of the explicit changes in patch 2, quoting:
> 
> >  - include arch/mips/vdso/vdso-image.o into UBSAN, GCOV, KCOV
> >  - include arch/sparc/vdso/vdso-image-*.o into UBSAN
> >  - include arch/sparc/vdso/vma.o into UBSAN
> >  - include arch/x86/entry/vdso/extable.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vdso-image-*.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vdso32-setup.o into KASAN, KCSAN, UBSAN, GCOV, KCOV
> >  - include arch/x86/entry/vdso/vma.o into GCOV, KCOV
> >  - include arch/x86/um/vdso/vma.o into KASAN, GCOV, KCOV
> 
> I would agree that these cases are all likely desirable.
> 
> Did you find any cases where you found that instrumentation was _removed_
> where not expected?
> 
> -Kees
> 


^ permalink raw reply	[flat|nested] 10+ messages in thread
end of thread, other threads:[~2024-05-14  7:32 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-05-06 13:35 [PATCH 0/3] kbuild: remove many tool coverage variables Masahiro Yamada
2024-05-06 13:35 ` [PATCH 1/3] kbuild: provide reasonable defaults for tool coverage Masahiro Yamada
2024-05-06 13:35 ` [PATCH 2/3] Makefile: remove redundant tool coverage variables Masahiro Yamada
2024-05-06 13:35 ` [PATCH 3/3] kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in scripts/Makefile.modfinal Masahiro Yamada
2024-05-13 18:48 ` [PATCH 0/3] kbuild: remove many tool coverage variables Kees Cook
2024-05-13 19:54   ` Marco Elver
2024-05-13 22:50     ` Masahiro Yamada
2024-05-13 22:39   ` Masahiro Yamada
2024-05-13 23:28     ` Kees Cook
2024-05-14  7:31   ` Roberto Sassu

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