[PATCH v7 0/5] Warn on orphan section placement

[PATCH v7 0/5] Warn on orphan section placement

[Kees Cook]

Hi Ingo,

The ever-shortening series. ;) Here is "v7", which is just the remaining
Makefile changes to enable orphan section warnings, now updated to
include ld-option calls.

Thanks for getting this all into -tip!

-Kees

v6: https://lore.kernel.org/lkml/20200821194310.3089815-1-keescook@chromium.org/
v5: https://lore.kernel.org/lkml/20200731230820.1742553-1-keescook@chromium.org/
v4: https://lore.kernel.org/lkml/20200629061840.4065483-1-keescook@chromium.org/
v3: https://lore.kernel.org/lkml/20200624014940.1204448-1-keescook@chromium.org/
v2: https://lore.kernel.org/lkml/20200622205815.2988115-1-keescook@chromium.org/
v1: https://lore.kernel.org/lkml/20200228002244.15240-1-keescook@chromium.org/

Kees Cook (5):
  arm64/build: Warn on orphan section placement
  arm/build: Warn on orphan section placement
  arm/boot: Warn on orphan section placement
  x86/build: Warn on orphan section placement
  x86/boot/compressed: Warn on orphan section placement

 arch/arm/Makefile                 | 4 ++++
 arch/arm/boot/compressed/Makefile | 2 ++
 arch/arm64/Makefile               | 4 ++++
 arch/x86/Makefile                 | 4 ++++
 arch/x86/boot/compressed/Makefile | 1 +
 5 files changed, 15 insertions(+)

-- 
2.25.1

[PATCH v7 0/5] Warn on orphan section placement

[Kees Cook]

Hi Ingo,

The ever-shortening series. ;) Here is "v7", which is just the remaining
Makefile changes to enable orphan section warnings, now updated to
include ld-option calls.

Thanks for getting this all into -tip!

-Kees

v6: https://lore.kernel.org/lkml/20200821194310.3089815-1-keescook@chromium.org/
v5: https://lore.kernel.org/lkml/20200731230820.1742553-1-keescook@chromium.org/
v4: https://lore.kernel.org/lkml/20200629061840.4065483-1-keescook@chromium.org/
v3: https://lore.kernel.org/lkml/20200624014940.1204448-1-keescook@chromium.org/
v2: https://lore.kernel.org/lkml/20200622205815.2988115-1-keescook@chromium.org/
v1: https://lore.kernel.org/lkml/20200228002244.15240-1-keescook@chromium.org/

Kees Cook (5):
  arm64/build: Warn on orphan section placement
  arm/build: Warn on orphan section placement
  arm/boot: Warn on orphan section placement
  x86/build: Warn on orphan section placement
  x86/boot/compressed: Warn on orphan section placement

 arch/arm/Makefile                 | 4 ++++
 arch/arm/boot/compressed/Makefile | 2 ++
 arch/arm64/Makefile               | 4 ++++
 arch/x86/Makefile                 | 4 ++++
 arch/x86/boot/compressed/Makefile | 1 +
 5 files changed, 15 insertions(+)

-- 
2.25.1


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v7 1/5] arm64/build: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

With all sections now handled, enable orphan section warnings.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm64/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 6de7f551b821..081144fcc3da 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -29,6 +29,10 @@ LDFLAGS_vmlinux	+= --fix-cortex-a53-843419
   endif
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y)
   ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y)
 $(warning LSE atomics not supported by binutils)
-- 
2.25.1

[PATCH v7 1/5] arm64/build: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

With all sections now handled, enable orphan section warnings.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm64/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 6de7f551b821..081144fcc3da 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -29,6 +29,10 @@ LDFLAGS_vmlinux	+= --fix-cortex-a53-843419
   endif
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y)
   ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y)
 $(warning LSE atomics not supported by binutils)
-- 
2.25.1


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v7 2/5] arm/build: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

Specifically, this would have made a recently fixed bug very obvious:

ld: warning: orphan section `.fixup' from `arch/arm/lib/copy_from_user.o' being placed in section `.fixup'

With all sections handled, enable orphan section warning.

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 4e877354515f..e589da3c8949 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -16,6 +16,10 @@ LDFLAGS_vmlinux	+= --be8
 KBUILD_LDFLAGS_MODULE	+= --be8
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
 KBUILD_LDS_MODULE	+= $(srctree)/arch/arm/kernel/module.lds
 endif
-- 
2.25.1

[PATCH v7 2/5] arm/build: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

Specifically, this would have made a recently fixed bug very obvious:

ld: warning: orphan section `.fixup' from `arch/arm/lib/copy_from_user.o' being placed in section `.fixup'

With all sections handled, enable orphan section warning.

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 4e877354515f..e589da3c8949 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -16,6 +16,10 @@ LDFLAGS_vmlinux	+= --be8
 KBUILD_LDFLAGS_MODULE	+= --be8
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
 KBUILD_LDS_MODULE	+= $(srctree)/arch/arm/kernel/module.lds
 endif
-- 
2.25.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v7 3/5] arm/boot: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.

With all sections now handled, enable orphan section warning.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm/boot/compressed/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index b1147b7f2c8d..58028abd05d9 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -123,6 +123,8 @@ endif
 LDFLAGS_vmlinux += --no-undefined
 # Delete all temporary local symbols
 LDFLAGS_vmlinux += -X
+# Report orphan sections
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
 # Next argument is a linker script
 LDFLAGS_vmlinux += -T
 
-- 
2.25.1

[PATCH v7 3/5] arm/boot: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.

With all sections now handled, enable orphan section warning.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm/boot/compressed/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index b1147b7f2c8d..58028abd05d9 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -123,6 +123,8 @@ endif
 LDFLAGS_vmlinux += --no-undefined
 # Delete all temporary local symbols
 LDFLAGS_vmlinux += -X
+# Report orphan sections
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
 # Next argument is a linker script
 LDFLAGS_vmlinux += -T
 
-- 
2.25.1


_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v7 4/5] x86/build: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.

Now that all sections are explicitly handled, enable orphan section
warnings.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 4346ffb2e39f..154259f18b8b 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
 LDFLAGS_vmlinux += -z max-page-size=0x200000
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 archscripts: scripts_basic
 	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
 
-- 
2.25.1

[PATCH v7 4/5] x86/build: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.

Now that all sections are explicitly handled, enable orphan section
warnings.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 4346ffb2e39f..154259f18b8b 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
 LDFLAGS_vmlinux += -z max-page-size=0x200000
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 archscripts: scripts_basic
 	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
 
-- 
2.25.1


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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v7 5/5] x86/boot/compressed: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

Now that all sections are explicitly handled, enable orphan section
warnings.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/boot/compressed/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 5b7f6e175b03..871cc071c925 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -54,6 +54,7 @@ KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info)
 # Compressed kernel should be built as PIE since it may be loaded at any
 # address by the bootloader.
 LDFLAGS_vmlinux := -pie $(call ld-option, --no-dynamic-linker)
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
 LDFLAGS_vmlinux += -T
 
 hostprogs	:= mkpiggy
-- 
2.25.1

[PATCH v7 5/5] x86/boot/compressed: Warn on orphan section placement

[Kees Cook]

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

Now that all sections are explicitly handled, enable orphan section
warnings.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/boot/compressed/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 5b7f6e175b03..871cc071c925 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -54,6 +54,7 @@ KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info)
 # Compressed kernel should be built as PIE since it may be loaded at any
 # address by the bootloader.
 LDFLAGS_vmlinux := -pie $(call ld-option, --no-dynamic-linker)
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
 LDFLAGS_vmlinux += -T
 
 hostprogs	:= mkpiggy
-- 
2.25.1


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Re: [PATCH v7 5/5] x86/boot/compressed: Warn on orphan section placement

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 8596 bytes --]

Hi Kees,

I love your patch! Perhaps something to improve:

[auto build test WARNING on tip/auto-latest]
[also build test WARNING on next-20200902]
[cannot apply to arm/for-next tip/x86/core v5.9-rc3]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Kees-Cook/Warn-on-orphan-section-placement/20200902-105541
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git d444af79439c392efe256742fb801a14f0793a71
config: x86_64-rhel (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce (this is a W=1 build):
        # save the attached .config to linux build tree
        make W=1 ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   ld: warning: orphan section `.gnu.version_d' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.gnu.version_d'
   ld: warning: orphan section `.gnu.version' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.gnu.version'
   ld: warning: orphan section `.gnu.version_r' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.gnu.version_r'
   ld: warning: orphan section `.dynsym' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.dynsym'
   ld: warning: orphan section `.dynstr' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.dynstr'
   ld: warning: orphan section `.dynamic' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.dynamic'
   ld: warning: orphan section `.hash' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.hash'
   ld: warning: orphan section `.gnu.hash' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.gnu.hash'
   ld: warning: orphan section `.plt' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.plt'
   ld: warning: orphan section `.dynbss' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.dynbss'
   ld: warning: orphan section `.plt.got' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.plt.got'
   ld: warning: orphan section `.eh_frame' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.eh_frame'
   ld: warning: orphan section `.eh_frame' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.eh_frame'
   ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/misc.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/misc.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/string.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/string.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/cmdline.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/cmdline.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/error.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/error.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/cpuflags.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/cpuflags.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/early_serial_console.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/early_serial_console.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/pgtable_64.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/pgtable_64.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/acpi.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/acpi.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/x86-stub.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/x86-stub.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/efi-stub-helper.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/efi-stub-helper.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/file.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/file.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/gop.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/gop.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/lib-cmdline.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/lib-cmdline.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/lib-ctype.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/lib-ctype.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/mem.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/mem.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/pci.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/pci.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/random.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/random.stub.o' being placed in section `.note.GNU-stack'
>> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/relocate.stub.o' being placed in section `.comment'
>> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/relocate.stub.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/secureboot.stub.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/secureboot.stub.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/skip_spaces.stub.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/skip_spaces.stub.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/tpm.stub.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/tpm.stub.o' being placed in section `.note.GNU-stack'
   ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/vsprintf.stub.o' being placed in section `.comment'
   ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/vsprintf.stub.o' being placed in section `.note.GNU-stack'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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Re: [PATCH v7 5/5] x86/boot/compressed: Warn on orphan section placement

[Kees Cook]

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On Wed, Sep 02, 2020 at 10:38:12PM +0800, kernel test robot wrote:
> Hi Kees,
> 
> I love your patch! Perhaps something to improve:
> 
> [auto build test WARNING on tip/auto-latest]
> [also build test WARNING on next-20200902]
> [cannot apply to arm/for-next tip/x86/core v5.9-rc3]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]

Hm, I think this is from having the wrong tree base (this is against
tip/build, but I'd kind of expect that to appear in tip/auto-latest, but
maybe I sent this series before auto-latest had updated with tip/build's
contents....)

Because all the warnings below are fixed in tip/build already...

I will double-check....

-Kees

> 
> url:    https://github.com/0day-ci/linux/commits/Kees-Cook/Warn-on-orphan-section-placement/20200902-105541
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git d444af79439c392efe256742fb801a14f0793a71
> config: x86_64-rhel (attached as .config)
> compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
> reproduce (this is a W=1 build):
>         # save the attached .config to linux build tree
>         make W=1 ARCH=x86_64 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All warnings (new ones prefixed by >>):
> 
>    ld: warning: orphan section `.gnu.version_d' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.gnu.version_d'
>    ld: warning: orphan section `.gnu.version' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.gnu.version'
>    ld: warning: orphan section `.gnu.version_r' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.gnu.version_r'
>    ld: warning: orphan section `.dynsym' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.dynsym'
>    ld: warning: orphan section `.dynstr' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.dynstr'
>    ld: warning: orphan section `.dynamic' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.dynamic'
>    ld: warning: orphan section `.hash' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.hash'
>    ld: warning: orphan section `.gnu.hash' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.gnu.hash'
>    ld: warning: orphan section `.plt' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.plt'
>    ld: warning: orphan section `.dynbss' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.dynbss'
>    ld: warning: orphan section `.plt.got' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.plt.got'
>    ld: warning: orphan section `.eh_frame' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.eh_frame'
>    ld: warning: orphan section `.eh_frame' from `arch/x86/boot/compressed/kernel_info.o' being placed in section `.eh_frame'
>    ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/misc.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/misc.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/string.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/string.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/cmdline.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/cmdline.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/error.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/error.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/cpuflags.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/cpuflags.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/early_serial_console.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/early_serial_console.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/pgtable_64.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/pgtable_64.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `arch/x86/boot/compressed/acpi.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `arch/x86/boot/compressed/acpi.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/x86-stub.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/x86-stub.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/efi-stub-helper.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/efi-stub-helper.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/file.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/file.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/gop.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/gop.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/lib-cmdline.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/lib-cmdline.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/lib-ctype.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/lib-ctype.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/mem.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/mem.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/pci.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/pci.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/random.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/random.stub.o' being placed in section `.note.GNU-stack'
> >> ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/relocate.stub.o' being placed in section `.comment'
> >> ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/relocate.stub.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/secureboot.stub.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/secureboot.stub.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/skip_spaces.stub.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/skip_spaces.stub.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/tpm.stub.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/tpm.stub.o' being placed in section `.note.GNU-stack'
>    ld: warning: orphan section `.comment' from `drivers/firmware/efi/libstub/vsprintf.stub.o' being placed in section `.comment'
>    ld: warning: orphan section `.note.GNU-stack' from `drivers/firmware/efi/libstub/vsprintf.stub.o' being placed in section `.note.GNU-stack'
> 
> ---
> 0-DAY CI Kernel Test Service, Intel Corporation
> https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org



-- 
Kees Cook

Re: [PATCH v7 0/5] Warn on orphan section placement

[Nick Desaulniers]

On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
>
> Hi Ingo,
>
> The ever-shortening series. ;) Here is "v7", which is just the remaining
> Makefile changes to enable orphan section warnings, now updated to
> include ld-option calls.
>
> Thanks for getting this all into -tip!

For the series,
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

As the recent ppc vdso boogaloo exposed, what about the vdsos?
* arch/x86/entry/vdso/Makefile
* arch/arm/vdso/Makefile
* arch/arm64/kernel/vdso/Makefile
* arch/arm64/kernel/vdso32/Makefile

>
> -Kees
>
> v6: https://lore.kernel.org/lkml/20200821194310.3089815-1-keescook@chromium.org/
> v5: https://lore.kernel.org/lkml/20200731230820.1742553-1-keescook@chromium.org/
> v4: https://lore.kernel.org/lkml/20200629061840.4065483-1-keescook@chromium.org/
> v3: https://lore.kernel.org/lkml/20200624014940.1204448-1-keescook@chromium.org/
> v2: https://lore.kernel.org/lkml/20200622205815.2988115-1-keescook@chromium.org/
> v1: https://lore.kernel.org/lkml/20200228002244.15240-1-keescook@chromium.org/
>
> Kees Cook (5):
>   arm64/build: Warn on orphan section placement
>   arm/build: Warn on orphan section placement
>   arm/boot: Warn on orphan section placement
>   x86/build: Warn on orphan section placement
>   x86/boot/compressed: Warn on orphan section placement
>
>  arch/arm/Makefile                 | 4 ++++
>  arch/arm/boot/compressed/Makefile | 2 ++
>  arch/arm64/Makefile               | 4 ++++
>  arch/x86/Makefile                 | 4 ++++
>  arch/x86/boot/compressed/Makefile | 1 +
>  5 files changed, 15 insertions(+)
>
> --
> 2.25.1
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH v7 0/5] Warn on orphan section placement

[Nick Desaulniers]

On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
>
> Hi Ingo,
>
> The ever-shortening series. ;) Here is "v7", which is just the remaining
> Makefile changes to enable orphan section warnings, now updated to
> include ld-option calls.
>
> Thanks for getting this all into -tip!

For the series,
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

As the recent ppc vdso boogaloo exposed, what about the vdsos?
* arch/x86/entry/vdso/Makefile
* arch/arm/vdso/Makefile
* arch/arm64/kernel/vdso/Makefile
* arch/arm64/kernel/vdso32/Makefile

>
> -Kees
>
> v6: https://lore.kernel.org/lkml/20200821194310.3089815-1-keescook@chromium.org/
> v5: https://lore.kernel.org/lkml/20200731230820.1742553-1-keescook@chromium.org/
> v4: https://lore.kernel.org/lkml/20200629061840.4065483-1-keescook@chromium.org/
> v3: https://lore.kernel.org/lkml/20200624014940.1204448-1-keescook@chromium.org/
> v2: https://lore.kernel.org/lkml/20200622205815.2988115-1-keescook@chromium.org/
> v1: https://lore.kernel.org/lkml/20200228002244.15240-1-keescook@chromium.org/
>
> Kees Cook (5):
>   arm64/build: Warn on orphan section placement
>   arm/build: Warn on orphan section placement
>   arm/boot: Warn on orphan section placement
>   x86/build: Warn on orphan section placement
>   x86/boot/compressed: Warn on orphan section placement
>
>  arch/arm/Makefile                 | 4 ++++
>  arch/arm/boot/compressed/Makefile | 2 ++
>  arch/arm64/Makefile               | 4 ++++
>  arch/x86/Makefile                 | 4 ++++
>  arch/x86/boot/compressed/Makefile | 1 +
>  5 files changed, 15 insertions(+)
>
> --
> 2.25.1
>


-- 
Thanks,
~Nick Desaulniers

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v7 0/5] Warn on orphan section placement

[Ingo Molnar]

* Nick Desaulniers <ndesaulniers@google.com> wrote:

> On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > Hi Ingo,
> >
> > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > Makefile changes to enable orphan section warnings, now updated to
> > include ld-option calls.
> >
> > Thanks for getting this all into -tip!
> 
> For the series,
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> 
> As the recent ppc vdso boogaloo exposed, what about the vdsos?
> * arch/x86/entry/vdso/Makefile
> * arch/arm/vdso/Makefile
> * arch/arm64/kernel/vdso/Makefile
> * arch/arm64/kernel/vdso32/Makefile

Kees, will these patches DTRT for the vDSO builds? I will be unable to test 
these patches on that old system until tomorrow the earliest.

I'm keeping these latest changes in WIP.core/build for now.

Thanks,

	Ingo

Re: [PATCH v7 0/5] Warn on orphan section placement

[Ingo Molnar]

* Nick Desaulniers <ndesaulniers@google.com> wrote:

> On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > Hi Ingo,
> >
> > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > Makefile changes to enable orphan section warnings, now updated to
> > include ld-option calls.
> >
> > Thanks for getting this all into -tip!
> 
> For the series,
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> 
> As the recent ppc vdso boogaloo exposed, what about the vdsos?
> * arch/x86/entry/vdso/Makefile
> * arch/arm/vdso/Makefile
> * arch/arm64/kernel/vdso/Makefile
> * arch/arm64/kernel/vdso32/Makefile

Kees, will these patches DTRT for the vDSO builds? I will be unable to test 
these patches on that old system until tomorrow the earliest.

I'm keeping these latest changes in WIP.core/build for now.

Thanks,

	Ingo

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v7 0/5] Warn on orphan section placement

[Kees Cook]

On Fri, Sep 04, 2020 at 07:58:25AM +0200, Ingo Molnar wrote:
> 
> * Nick Desaulniers <ndesaulniers@google.com> wrote:
> 
> > On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> > >
> > > Hi Ingo,
> > >
> > > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > > Makefile changes to enable orphan section warnings, now updated to
> > > include ld-option calls.
> > >
> > > Thanks for getting this all into -tip!
> > 
> > For the series,
> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> > 
> > As the recent ppc vdso boogaloo exposed, what about the vdsos?
> > * arch/x86/entry/vdso/Makefile
> > * arch/arm/vdso/Makefile
> > * arch/arm64/kernel/vdso/Makefile
> > * arch/arm64/kernel/vdso32/Makefile
> 
> Kees, will these patches DTRT for the vDSO builds? I will be unable to test 
> these patches on that old system until tomorrow the earliest.

I would like to see VDSO done next, but it's entirely separate from
this series. This series only touches the core kernel build (i.e. via the
interactions with scripts/link-vmlinux.sh) or the boot stubs. So there
is no impact on VDSO linking.

> I'm keeping these latest changes in WIP.core/build for now.

They should be safe to land in -next, which is important so we can shake
out any other sneaky sections that all our existing testing hasn't
found. :)

-- 
Kees Cook

Re: [PATCH v7 0/5] Warn on orphan section placement

[Kees Cook]

On Fri, Sep 04, 2020 at 07:58:25AM +0200, Ingo Molnar wrote:
> 
> * Nick Desaulniers <ndesaulniers@google.com> wrote:
> 
> > On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> > >
> > > Hi Ingo,
> > >
> > > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > > Makefile changes to enable orphan section warnings, now updated to
> > > include ld-option calls.
> > >
> > > Thanks for getting this all into -tip!
> > 
> > For the series,
> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> > 
> > As the recent ppc vdso boogaloo exposed, what about the vdsos?
> > * arch/x86/entry/vdso/Makefile
> > * arch/arm/vdso/Makefile
> > * arch/arm64/kernel/vdso/Makefile
> > * arch/arm64/kernel/vdso32/Makefile
> 
> Kees, will these patches DTRT for the vDSO builds? I will be unable to test 
> these patches on that old system until tomorrow the earliest.

I would like to see VDSO done next, but it's entirely separate from
this series. This series only touches the core kernel build (i.e. via the
interactions with scripts/link-vmlinux.sh) or the boot stubs. So there
is no impact on VDSO linking.

> I'm keeping these latest changes in WIP.core/build for now.

They should be safe to land in -next, which is important so we can shake
out any other sneaky sections that all our existing testing hasn't
found. :)

-- 
Kees Cook

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v7 4/5] x86/build: Warn on orphan section placement

[Arvind Sankar]

On Tue, Sep 01, 2020 at 07:53:46PM -0700, Kees Cook wrote:
> We don't want to depend on the linker's orphan section placement
> heuristics as these can vary between linkers, and may change between
> versions. All sections need to be explicitly handled in the linker script.
> 
> Now that all sections are explicitly handled, enable orphan section
> warnings.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  arch/x86/Makefile | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 4346ffb2e39f..154259f18b8b 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
>  LDFLAGS_vmlinux += -z max-page-size=0x200000
>  endif
>  
> +# We never want expected sections to be placed heuristically by the
> +# linker. All sections should be explicitly named in the linker script.
> +LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
> +
>  archscripts: scripts_basic
>  	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
>  
> -- 
> 2.25.1
> 

With LLVM=1 and GCOV_KERNEL/GCOV_PROFILE_ALL enabled, there are
.eh_frame sections created. I see that KASAN and KCSAN currently discard
them. Does GCOV actually need them or should it also discard?

Thanks.

Re: [PATCH v7 4/5] x86/build: Warn on orphan section placement

[Arvind Sankar]

On Tue, Sep 01, 2020 at 07:53:46PM -0700, Kees Cook wrote:
> We don't want to depend on the linker's orphan section placement
> heuristics as these can vary between linkers, and may change between
> versions. All sections need to be explicitly handled in the linker script.
> 
> Now that all sections are explicitly handled, enable orphan section
> warnings.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  arch/x86/Makefile | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 4346ffb2e39f..154259f18b8b 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
>  LDFLAGS_vmlinux += -z max-page-size=0x200000
>  endif
>  
> +# We never want expected sections to be placed heuristically by the
> +# linker. All sections should be explicitly named in the linker script.
> +LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
> +
>  archscripts: scripts_basic
>  	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
>  
> -- 
> 2.25.1
> 

With LLVM=1 and GCOV_KERNEL/GCOV_PROFILE_ALL enabled, there are
.eh_frame sections created. I see that KASAN and KCSAN currently discard
them. Does GCOV actually need them or should it also discard?

Thanks.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v7 0/5] Warn on orphan section placement

[Ingo Molnar]

* Kees Cook <keescook@chromium.org> wrote:

> On Fri, Sep 04, 2020 at 07:58:25AM +0200, Ingo Molnar wrote:
> > 
> > * Nick Desaulniers <ndesaulniers@google.com> wrote:
> > 
> > > On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> > > >
> > > > Hi Ingo,
> > > >
> > > > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > > > Makefile changes to enable orphan section warnings, now updated to
> > > > include ld-option calls.
> > > >
> > > > Thanks for getting this all into -tip!
> > > 
> > > For the series,
> > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> > > 
> > > As the recent ppc vdso boogaloo exposed, what about the vdsos?
> > > * arch/x86/entry/vdso/Makefile
> > > * arch/arm/vdso/Makefile
> > > * arch/arm64/kernel/vdso/Makefile
> > > * arch/arm64/kernel/vdso32/Makefile
> > 
> > Kees, will these patches DTRT for the vDSO builds? I will be unable to test 
> > these patches on that old system until tomorrow the earliest.
> 
> I would like to see VDSO done next, but it's entirely separate from
> this series. This series only touches the core kernel build (i.e. via the
> interactions with scripts/link-vmlinux.sh) or the boot stubs. So there
> is no impact on VDSO linking.

Great!

I also double checked that things still build fine with ancient LD.

> > I'm keeping these latest changes in WIP.core/build for now.
> 
> They should be safe to land in -next, which is important so we can shake
> out any other sneaky sections that all our existing testing hasn't
> found. :)

OK, cool - I've graduated them over into tip:core/build. :-)

Thanks,

	Ingo

Re: [PATCH v7 0/5] Warn on orphan section placement

[Ingo Molnar]

* Kees Cook <keescook@chromium.org> wrote:

> On Fri, Sep 04, 2020 at 07:58:25AM +0200, Ingo Molnar wrote:
> > 
> > * Nick Desaulniers <ndesaulniers@google.com> wrote:
> > 
> > > On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> > > >
> > > > Hi Ingo,
> > > >
> > > > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > > > Makefile changes to enable orphan section warnings, now updated to
> > > > include ld-option calls.
> > > >
> > > > Thanks for getting this all into -tip!
> > > 
> > > For the series,
> > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> > > 
> > > As the recent ppc vdso boogaloo exposed, what about the vdsos?
> > > * arch/x86/entry/vdso/Makefile
> > > * arch/arm/vdso/Makefile
> > > * arch/arm64/kernel/vdso/Makefile
> > > * arch/arm64/kernel/vdso32/Makefile
> > 
> > Kees, will these patches DTRT for the vDSO builds? I will be unable to test 
> > these patches on that old system until tomorrow the earliest.
> 
> I would like to see VDSO done next, but it's entirely separate from
> this series. This series only touches the core kernel build (i.e. via the
> interactions with scripts/link-vmlinux.sh) or the boot stubs. So there
> is no impact on VDSO linking.

Great!

I also double checked that things still build fine with ancient LD.

> > I'm keeping these latest changes in WIP.core/build for now.
> 
> They should be safe to land in -next, which is important so we can shake
> out any other sneaky sections that all our existing testing hasn't
> found. :)

OK, cool - I've graduated them over into tip:core/build. :-)

Thanks,

	Ingo

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[tip: core/build] x86/boot/compressed: Warn on orphan section placement

[tip-bot2 for Kees Cook]

The following commit has been merged into the core/build branch of tip:

Commit-ID:     6e0bf0e0e55000742a53c5f3b58f8669e0091a11
Gitweb:        https://git.kernel.org/tip/6e0bf0e0e55000742a53c5f3b58f8669e0091a11
Author:        Kees Cook <keescook@chromium.org>
AuthorDate:    Tue, 01 Sep 2020 19:53:47 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 03 Sep 2020 10:28:36 +02:00

x86/boot/compressed: Warn on orphan section placement

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

Now that all sections are explicitly handled, enable orphan section
warnings.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20200902025347.2504702-6-keescook@chromium.org
---
 arch/x86/boot/compressed/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 5b7f6e1..871cc07 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -54,6 +54,7 @@ KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info)
 # Compressed kernel should be built as PIE since it may be loaded at any
 # address by the bootloader.
 LDFLAGS_vmlinux := -pie $(call ld-option, --no-dynamic-linker)
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
 LDFLAGS_vmlinux += -T
 
 hostprogs	:= mkpiggy

[tip: core/build] x86/build: Warn on orphan section placement

[tip-bot2 for Kees Cook]

The following commit has been merged into the core/build branch of tip:

Commit-ID:     83109d5d5fba7abf362f5a443c9f4c4ea10bbc8d
Gitweb:        https://git.kernel.org/tip/83109d5d5fba7abf362f5a443c9f4c4ea10bbc8d
Author:        Kees Cook <keescook@chromium.org>
AuthorDate:    Tue, 01 Sep 2020 19:53:46 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 03 Sep 2020 10:28:36 +02:00

x86/build: Warn on orphan section placement

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.

Now that all sections are explicitly handled, enable orphan section
warnings.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20200902025347.2504702-5-keescook@chromium.org
---
 arch/x86/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 4346ffb..154259f 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
 LDFLAGS_vmlinux += -z max-page-size=0x200000
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 archscripts: scripts_basic
 	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
 

[tip: core/build] arm64/build: Warn on orphan section placement

[tip-bot2 for Kees Cook]

The following commit has been merged into the core/build branch of tip:

Commit-ID:     b3e5d80d0c48c0cc7bce56473672f4e6e1210910
Gitweb:        https://git.kernel.org/tip/b3e5d80d0c48c0cc7bce56473672f4e6e1210910
Author:        Kees Cook <keescook@chromium.org>
AuthorDate:    Tue, 01 Sep 2020 19:53:43 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 03 Sep 2020 10:28:35 +02:00

arm64/build: Warn on orphan section placement

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

With all sections now handled, enable orphan section warnings.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20200902025347.2504702-2-keescook@chromium.org
---
 arch/arm64/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 6de7f55..081144f 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -29,6 +29,10 @@ LDFLAGS_vmlinux	+= --fix-cortex-a53-843419
   endif
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y)
   ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y)
 $(warning LSE atomics not supported by binutils)

[tip: core/build] arm/build: Warn on orphan section placement

[tip-bot2 for Kees Cook]

The following commit has been merged into the core/build branch of tip:

Commit-ID:     5a17850e251a55bba6d65aefbfeacfa9888cd2cd
Gitweb:        https://git.kernel.org/tip/5a17850e251a55bba6d65aefbfeacfa9888cd2cd
Author:        Kees Cook <keescook@chromium.org>
AuthorDate:    Tue, 01 Sep 2020 19:53:44 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 03 Sep 2020 10:28:35 +02:00

arm/build: Warn on orphan section placement

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.

Specifically, this would have made a recently fixed bug very obvious:

ld: warning: orphan section `.fixup' from `arch/arm/lib/copy_from_user.o' being placed in section `.fixup'

With all sections handled, enable orphan section warning.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20200902025347.2504702-3-keescook@chromium.org
---
 arch/arm/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 4e87735..e589da3 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -16,6 +16,10 @@ LDFLAGS_vmlinux	+= --be8
 KBUILD_LDFLAGS_MODULE	+= --be8
 endif
 
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
 ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
 KBUILD_LDS_MODULE	+= $(srctree)/arch/arm/kernel/module.lds
 endif

[tip: core/build] arm/boot: Warn on orphan section placement

[tip-bot2 for Kees Cook]

The following commit has been merged into the core/build branch of tip:

Commit-ID:     4409d2f8dfe7d5088567d4ba00133f876ee586c7
Gitweb:        https://git.kernel.org/tip/4409d2f8dfe7d5088567d4ba00133f876ee586c7
Author:        Kees Cook <keescook@chromium.org>
AuthorDate:    Tue, 01 Sep 2020 19:53:45 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Thu, 03 Sep 2020 10:28:35 +02:00

arm/boot: Warn on orphan section placement

We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.

With all sections now handled, enable orphan section warning.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20200902025347.2504702-4-keescook@chromium.org
---
 arch/arm/boot/compressed/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index b1147b7..58028ab 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -123,6 +123,8 @@ endif
 LDFLAGS_vmlinux += --no-undefined
 # Delete all temporary local symbols
 LDFLAGS_vmlinux += -X
+# Report orphan sections
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
 # Next argument is a linker script
 LDFLAGS_vmlinux += -T
 

Re: [PATCH v7 4/5] x86/build: Warn on orphan section placement

[Arvind Sankar]

On Sat, Sep 05, 2020 at 06:48:35PM -0400, Arvind Sankar wrote:
> On Tue, Sep 01, 2020 at 07:53:46PM -0700, Kees Cook wrote:
> > We don't want to depend on the linker's orphan section placement
> > heuristics as these can vary between linkers, and may change between
> > versions. All sections need to be explicitly handled in the linker script.
> > 
> > Now that all sections are explicitly handled, enable orphan section
> > warnings.
> > 
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> >  arch/x86/Makefile | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> > index 4346ffb2e39f..154259f18b8b 100644
> > --- a/arch/x86/Makefile
> > +++ b/arch/x86/Makefile
> > @@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
> >  LDFLAGS_vmlinux += -z max-page-size=0x200000
> >  endif
> >  
> > +# We never want expected sections to be placed heuristically by the
> > +# linker. All sections should be explicitly named in the linker script.
> > +LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
> > +
> >  archscripts: scripts_basic
> >  	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
> >  
> > -- 
> > 2.25.1
> > 
> 
> With LLVM=1 and GCOV_KERNEL/GCOV_PROFILE_ALL enabled, there are
> .eh_frame sections created. I see that KASAN and KCSAN currently discard
> them. Does GCOV actually need them or should it also discard?
> 
> Thanks.

Also, with LLD 10.0.1 which is going to be the minimum supported
version, the relocation sections etc still generate warnings.

ld.lld: warning:
arch/x86/video/built-in.a(fbdev.o):(.rela.orc_unwind_ip) is being placed
in '.rela.orc_unwind_ip'
ld.lld: warning: .tmp_vmlinux.kallsyms2.o:(.rela.rodata) is being placed
in '.rela.rodata'
ld.lld: warning: <internal>:(.bss.rel.ro) is being placed in
'.bss.rel.ro'
ld.lld: warning: <internal>:(.eh_frame) is being placed in '.eh_frame'
ld.lld: warning: <internal>:(.symtab_shndx) is being placed in
'.symtab_shndx'

Re: [PATCH v7 4/5] x86/build: Warn on orphan section placement

[Arvind Sankar]

On Sat, Sep 05, 2020 at 06:48:35PM -0400, Arvind Sankar wrote:
> On Tue, Sep 01, 2020 at 07:53:46PM -0700, Kees Cook wrote:
> > We don't want to depend on the linker's orphan section placement
> > heuristics as these can vary between linkers, and may change between
> > versions. All sections need to be explicitly handled in the linker script.
> > 
> > Now that all sections are explicitly handled, enable orphan section
> > warnings.
> > 
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> >  arch/x86/Makefile | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> > index 4346ffb2e39f..154259f18b8b 100644
> > --- a/arch/x86/Makefile
> > +++ b/arch/x86/Makefile
> > @@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
> >  LDFLAGS_vmlinux += -z max-page-size=0x200000
> >  endif
> >  
> > +# We never want expected sections to be placed heuristically by the
> > +# linker. All sections should be explicitly named in the linker script.
> > +LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
> > +
> >  archscripts: scripts_basic
> >  	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
> >  
> > -- 
> > 2.25.1
> > 
> 
> With LLVM=1 and GCOV_KERNEL/GCOV_PROFILE_ALL enabled, there are
> .eh_frame sections created. I see that KASAN and KCSAN currently discard
> them. Does GCOV actually need them or should it also discard?
> 
> Thanks.

Also, with LLD 10.0.1 which is going to be the minimum supported
version, the relocation sections etc still generate warnings.

ld.lld: warning:
arch/x86/video/built-in.a(fbdev.o):(.rela.orc_unwind_ip) is being placed
in '.rela.orc_unwind_ip'
ld.lld: warning: .tmp_vmlinux.kallsyms2.o:(.rela.rodata) is being placed
in '.rela.rodata'
ld.lld: warning: <internal>:(.bss.rel.ro) is being placed in
'.bss.rel.ro'
ld.lld: warning: <internal>:(.eh_frame) is being placed in '.eh_frame'
ld.lld: warning: <internal>:(.symtab_shndx) is being placed in
'.symtab_shndx'

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