Re: [PATCH v4] Makefile.compiler: replace cc-ifversion with compiler-specific macros

From: Nick Desaulniers
Date: Mon May 15 2023 - 19:02:03 EST

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On Wed, May 3, 2023 at 3:33 PM Shreeya Patel
<shreeya.patel@xxxxxxxxxxxxx> wrote:
>
>
> On 04/05/23 02:45, Nick Desaulniers wrote:
> > On Wed, May 3, 2023 at 2:02 PM Shreeya Patel
> > <shreeya.patel@xxxxxxxxxxxxx> wrote:
> >> Hi Nick,
> >>
> >> On 28/04/23 22:57, Nick Desaulniers wrote:
> >>> On Thu, Apr 27, 2023 at 4:54 AM Shreeya Patel
> >>> <shreeya.patel@xxxxxxxxxxxxx> wrote:
> >>>> Hi Nick,
> >>>>
> >>>> On 19/09/22 22:38, Nick Desaulniers wrote:
> >>>>> cc-ifversion is GCC specific. Replace it with compiler specific
> >>>>> variants. Update the users of cc-ifversion to use these new macros.
> >>>>>
> >>>>> Link: https://github.com/ClangBuiltLinux/linux/issues/350
> >>>>> Link: https://lore.kernel.org/llvm/CAGG=3QWSAUakO42kubrCap8fp-gm1ERJJAYXTnP1iHk_wrH=BQ@xxxxxxxxxxxxxx/
> >>>>> Suggested-by: Bill Wendling <morbo@xxxxxxxxxx>
> >>>>> Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>
> >>>>> Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
> >>>> KernelCI found this patch causes a regression in the
> >>>> baseline.logintest on qemu_arm-virt-gicv3-uefi [1],
> >>>> see the bisection report for more details [2].
> >>>>
> >>>> Let me know if you have any questions.
> >>>>
> >>>>
> >>>> [1] https://linux.kernelci.org/test/case/id/644596a0beca2ead032e8669/
> >>> Hi Shreeya,
> >>> Thanks for the report.
> >>>
> >>> When I click the above link, then click `multi_v7_defconfig+debug` to
> >>> get the config necessary to reproduce, I get an HTTP 404.
> >>> https://storage.kernelci.org/mainline/master/v6.3/arm/multi_v7_defconfig+debug/gcc-10/kernel.config
> >>>
> >>> Same for zImage
> >>> https://storage.kernelci.org/mainline/master/v6.3/arm/multi_v7_defconfig+debug/gcc-10/zImage
> >> Apologies for the broken links. We will try to fix the important ones if
> >> we can but in the meantime,
> >> following is the correct link that you can refer.
> >>
> >> config :-
> >> https://storage.kernelci.org/mainline/master/v6.3/arm/multi_v7_defconfig+debug/gcc-10/config/kernel.config
> >>
> >> zImage :-
> >> https://storage.kernelci.org/mainline/master/v6.3/arm/multi_v7_defconfig+debug/gcc-10/kernel/zImage
> >>
> >> If you notice, they are present under the kernel directory and same way
> >> you can find links for other kernel
> >> builds if you'd like to check them out.
> >>
> >>> If I click on the log
> >>> https://storage.kernelci.org/mainline/master/v6.3/arm/multi_v7_defconfig+debug/gcc-10/lab-collabora/baseline-qemu_arm-virt-gicv3-uefi.txt
> >>> It looks like the machine powered up, then powered off. Is the test
> >>> actually failing?
> >> I recommend checking the html logs from the kernelci dashboard.
> >> Also, FYI baseline.login test failure means that the device failed to
> >> boot which I think is causing by the issues that you pointed out.
> >>
> >> <3>[ 0.417001][ T1] UBSAN: array-index-out-of-bounds in
> >> ../arch/arm/mach-sunxi/mc_smp.c:811:29
> >>
> >> And potentially another issue with ftrace
> >>
> >> <4>[ 0.000000][ T0] WARNING: CPU: 0 PID: 0 at
> >> kernel/trace/ftrace.c:2176 ftrace_bug+0x340/0x3b4
> >>
> >>
> >> Let me know if you need more information from my side to reproduce this
> >> on your end.
> >>
> >>
> >> Thanks,
> >> Shreeya Patel
> > Hi Shreeya,
> > I may need your help to reproduce the failure.

Hi Shreeya,
Sorry for the delay, I was out traveling last week. I still need help
reproducing. Trying this again from scratch, my VM is now failing to
boot regardless of whether I revert the patch in question or not.

Can you please help verify this failure by hand, and see if applying
https://github.com/ClangBuiltLinux/linux/commit/45c4fb6095d872785e077942da896d65d87ab56b.patch
helps? If you can repro; mind sharing your precise steps to reproduce?

> >
> > $ wget https://storage.kernelci.org/mainline/master/v6.3/arm/multi_v7_defconfig+debug/gcc-10/config/kernel.config
> > -O .config
> > $ ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- make -j128 olddefconfig all -s
> > <launch qemu>
> > / # mount -t proc /proc
> > / # cat /proc/version
> > Linux version 6.3.0 (root@61385772abae) (arm-linux-gnueabihf-gcc
> > (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian)
> > 2.35.2) #2 SMP Wed May 3 21:10:27 UTC 2023
> >
> > I was able to boot the resulting kernel to a command line. Perhaps
> > there's something about the userspace image that tickles this? Can you
> > supply the rootfs that's used in testing?
>
>
> Following is the link to the rootfs for a different kernel build which
> has the same test case failing.
> http://storage.kernelci.org/images/rootfs/buildroot/buildroot-baseline/20230414.0/armel/rootfs.cpio.gz
>
>
> Lava job :-
> https://lava.collabora.dev/scheduler/job/10135631
>
> You can usually get the rootfs link and many more information through
> the "definition" present on Lava job dashboard.
>
> Kernelci test id for the above job :-
> https://linux.kernelci.org/test/case/id/64497865a4bab57def2e85e8/
>
>
> Thanks,
> Shreeya Patel
>
> >>> I was able to boot ARCH=arm defconfig with CC=arm-linux-gnueabihf-gcc
> >>> (Debian 10.2.1-6) in QEMU just fine. So I'm going to need some more
> >>> information to help reproduce what specifically is failing.
> >>>
> >>> Linux version 6.3.0 (root@61385772abae) (arm-linux-gnueabihf-gcc
> >>> (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian)
> >>> 2.35.2) #1 SMP Fri Apr 28 17:19:59 UTC 2023
> >>>
> >>> ---
> >>>
> >>> It does look like UBSAN is flagging an array OOB:
> >>>
> >>> <3>[ 0.417001][ T1] UBSAN: array-index-out-of-bounds in
> >>> ../arch/arm/mach-sunxi/mc_smp.c:811:29
> >>>
> >>> And potentially another issue with ftrace
> >>>
> >>> <4>[ 0.000000][ T0] WARNING: CPU: 0 PID: 0 at
> >>> kernel/trace/ftrace.c:2176 ftrace_bug+0x340/0x3b4
> >>>
> >>>
> >>>
> >>>> [2] https://groups.io/g/kernelci-results/message/40804
> >>>>
> >>>>
> >>>> Thanks,
> >>>> Shreeya Patel
> >>>>
> >>>> #regzbot introduced: 88b61e3bff93
> >>>>
> >>>>> ---
> >>>>> Changes v3 -> v4:
> >>>>> * Split into its own patch again from series, as per Masahiro.
> >>>>> * Rebase on top of b0839b281c427e844143dba3893e25c83cdd6c17 and update
> >>>>> clang -Wformat logic in scripts/Makefile.extrawarn, as per Masahiro.
> >>>>>
> >>>>> Documentation/kbuild/makefiles.rst | 29 ++++++++++++---------
> >>>>> Makefile | 6 ++---
> >>>>> drivers/gpu/drm/amd/display/dc/dml/Makefile | 2 +-
> >>>>> scripts/Makefile.compiler | 10 ++++---
> >>>>> scripts/Makefile.extrawarn | 4 +--
> >>>>> 5 files changed, 29 insertions(+), 22 deletions(-)
> >>>>>
> >>>>> diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
> >>>>> index 11a296e52d68..ee7e3ea1fbe1 100644
> >>>>> --- a/Documentation/kbuild/makefiles.rst
> >>>>> +++ b/Documentation/kbuild/makefiles.rst
> >>>>> @@ -682,22 +682,27 @@ more details, with real examples.
> >>>>> In the above example, -Wno-unused-but-set-variable will be added to
> >>>>> KBUILD_CFLAGS only if gcc really accepts it.
> >>>>>
> >>>>> - cc-ifversion
> >>>>> - cc-ifversion tests the version of $(CC) and equals the fourth parameter
> >>>>> - if version expression is true, or the fifth (if given) if the version
> >>>>> - expression is false.
> >>>>> + gcc-min-version
> >>>>> + gcc-min-version tests if the value of $(CONFIG_GCC_VERSION) is greater than
> >>>>> + or equal to the provided value and evaluates to y if so.
> >>>>>
> >>>>> Example::
> >>>>>
> >>>>> - #fs/reiserfs/Makefile
> >>>>> - ccflags-y := $(call cc-ifversion, -lt, 0402, -O1)
> >>>>> + cflags-$(call gcc-min-version, 70100) := -foo
> >>>>>
> >>>>> - In this example, ccflags-y will be assigned the value -O1 if the
> >>>>> - $(CC) version is less than 4.2.
> >>>>> - cc-ifversion takes all the shell operators:
> >>>>> - -eq, -ne, -lt, -le, -gt, and -ge
> >>>>> - The third parameter may be a text as in this example, but it may also
> >>>>> - be an expanded variable or a macro.
> >>>>> + In this example, cflags-y will be assigned the value -foo if $(CC) is gcc and
> >>>>> + $(CONFIG_GCC_VERSION) is >= 7.1.
> >>>>> +
> >>>>> + clang-min-version
> >>>>> + clang-min-version tests if the value of $(CONFIG_CLANG_VERSION) is greater
> >>>>> + than or equal to the provided value and evaluates to y if so.
> >>>>> +
> >>>>> + Example::
> >>>>> +
> >>>>> + cflags-$(call clang-min-version, 110000) := -foo
> >>>>> +
> >>>>> + In this example, cflags-y will be assigned the value -foo if $(CC) is clang
> >>>>> + and $(CONFIG_CLANG_VERSION) is >= 11.0.0.
> >>>>>
> >>>>> cc-cross-prefix
> >>>>> cc-cross-prefix is used to check if there exists a $(CC) in path with
> >>>>> diff --git a/Makefile b/Makefile
> >>>>> index 298f69060f10..411c8480b37e 100644
> >>>>> --- a/Makefile
> >>>>> +++ b/Makefile
> >>>>> @@ -790,7 +790,6 @@ KBUILD_CFLAGS += $(stackp-flags-y)
> >>>>>
> >>>>> KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror
> >>>>> KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
> >>>>> -KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
> >>>>>
> >>>>> ifdef CONFIG_CC_IS_CLANG
> >>>>> KBUILD_CPPFLAGS += -Qunused-arguments
> >>>>> @@ -972,7 +971,6 @@ ifdef CONFIG_CC_IS_GCC
> >>>>> KBUILD_CFLAGS += -Wno-maybe-uninitialized
> >>>>> endif
> >>>>>
> >>>>> -ifdef CONFIG_CC_IS_GCC
> >>>>> # The allocators already balk at large sizes, so silence the compiler
> >>>>> # warnings for bounds checks involving those possible values. While
> >>>>> # -Wno-alloc-size-larger-than would normally be used here, earlier versions
> >>>>> @@ -984,8 +982,8 @@ ifdef CONFIG_CC_IS_GCC
> >>>>> # ignored, continuing to default to PTRDIFF_MAX. So, left with no other
> >>>>> # choice, we must perform a versioned check to disable this warning.
> >>>>> # https://lore.kernel.org/lkml/20210824115859.187f272f@xxxxxxxxxxxxxxxx
> >>>>> -KBUILD_CFLAGS += $(call cc-ifversion, -ge, 0901, -Wno-alloc-size-larger-than)
> >>>>> -endif
> >>>>> +KBUILD_CFLAGS-$(call gcc-min-version, 90100) += -Wno-alloc-size-larger-than
> >>>>> +KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
> >>>>>
> >>>>> # disable invalid "can't wrap" optimizations for signed / pointers
> >>>>> KBUILD_CFLAGS += -fno-strict-overflow
> >>>>> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> >>>>> index cb81ed2fbd53..d70838edba80 100644
> >>>>> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
> >>>>> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
> >>>>> @@ -34,7 +34,7 @@ dml_ccflags := -mhard-float -maltivec
> >>>>> endif
> >>>>>
> >>>>> ifdef CONFIG_CC_IS_GCC
> >>>>> -ifeq ($(call cc-ifversion, -lt, 0701, y), y)
> >>>>> +ifneq ($(call gcc-min-version, 70100),y)
> >>>>> IS_OLD_GCC = 1
> >>>>> endif
> >>>>> endif
> >>>>> diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler
> >>>>> index 94d0d40cddb3..9d18fb91890e 100644
> >>>>> --- a/scripts/Makefile.compiler
> >>>>> +++ b/scripts/Makefile.compiler
> >>>>> @@ -61,9 +61,13 @@ cc-option-yn = $(call try-run,\
> >>>>> cc-disable-warning = $(call try-run,\
> >>>>> $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1)))
> >>>>>
> >>>>> -# cc-ifversion
> >>>>> -# Usage: EXTRA_CFLAGS += $(call cc-ifversion, -lt, 0402, -O1)
> >>>>> -cc-ifversion = $(shell [ $(CONFIG_GCC_VERSION)0 $(1) $(2)000 ] && echo $(3) || echo $(4))
> >>>>> +# gcc-min-version
> >>>>> +# Usage: cflags-$(call gcc-min-version, 70100) += -foo
> >>>>> +gcc-min-version = $(shell [ $(CONFIG_GCC_VERSION) -ge $(1) ] && echo y)
> >>>>> +
> >>>>> +# clang-min-version
> >>>>> +# Usage: cflags-$(call clang-min-version, 110000) += -foo
> >>>>> +clang-min-version = $(shell [ $(CONFIG_CLANG_VERSION) -ge $(1) ] && echo y)
> >>>>>
> >>>>> # ld-option
> >>>>> # Usage: KBUILD_LDFLAGS += $(call ld-option, -X, -Y)
> >>>>> diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
> >>>>> index 6ae482158bc4..5769c1939d40 100644
> >>>>> --- a/scripts/Makefile.extrawarn
> >>>>> +++ b/scripts/Makefile.extrawarn
> >>>>> @@ -48,7 +48,7 @@ else
> >>>>> ifdef CONFIG_CC_IS_CLANG
> >>>>> KBUILD_CFLAGS += -Wno-initializer-overrides
> >>>>> # Clang before clang-16 would warn on default argument promotions.
> >>>>> -ifeq ($(shell [ $(CONFIG_CLANG_VERSION) -lt 160000 ] && echo y),y)
> >>>>> +ifneq ($(call clang-min-version, 160000),y)
> >>>>> # Disable -Wformat
> >>>>> KBUILD_CFLAGS += -Wno-format
> >>>>> # Then re-enable flags that were part of the -Wformat group that aren't
> >>>>> @@ -56,7 +56,7 @@ KBUILD_CFLAGS += -Wno-format
> >>>>> KBUILD_CFLAGS += -Wformat-extra-args -Wformat-invalid-specifier
> >>>>> KBUILD_CFLAGS += -Wformat-zero-length -Wnonnull
> >>>>> # Requires clang-12+.
> >>>>> -ifeq ($(shell [ $(CONFIG_CLANG_VERSION) -ge 120000 ] && echo y),y)
> >>>>> +ifeq ($(call clang-min-version, 120000),y)
> >>>>> KBUILD_CFLAGS += -Wformat-insufficient-args
> >>>>> endif
> >>>>> endif
> >>>
> >
> >

--
Thanks,
~Nick Desaulniers

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