Re: [linux-next:master 1016/2825] make[2]: *** kselftest/livepatch/test_modules: No such file or directory. Stop.

[Marcos Paulo de Souza <mpdesouza@suse.com>]

CC'ing Miroslav, as he was also involved in the patchset and can have
some ideas about how to fix this issue.

On Wed, 2024-01-31 at 15:39 -0300, Marcos Paulo de Souza wrote:
> On Wed, 2024-01-31 at 16:34 +0100, Petr Mladek wrote:
> > On Tue 2024-01-30 11:39:56, Marcos Paulo de Souza wrote:
> > > On Tue, 2024-01-30 at 07:08 +0800, kernel test robot wrote:
> > > > tree:  
> > > > https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> > > >  m
> > > > aster
> > > > head:   596764183be8ebb13352b281a442a1f1151c9b06
> > > > commit: c4bbe83d27c2446a033cc0381c3fb6be5e8c41c7 [1016/2825]
> > > > livepatch: Move tests from lib/livepatch to selftests/livepatch
> > > > compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> > > > reproduce (this is a W=1 build):
> > > > (
> > > > https://download.01.org/0day-ci/archive/20240130/202401300736.GkSZ
> > > > oS
> > > > rA-lkp@intel.com/reproduce)
> > > > 
> > > When looking at the lib.mk, I just followed the other variables
> > > and
> > > did
> > > the same:
> > > 
> > > TEST_GEN_MODS_DIR := $(patsubst
> > > %,$(OUTPUT)/%,$(TEST_GEN_MODS_DIR))
> > > 
> > > But later on, I jump into $(TEST_GEN_MODS_DIR), which is invalid
> > > because of the O= that is used a prefix for the path:
> > > /tmp/kselftest/kselftest/livepatch/test_modules. My first idea
> > > was
> > > to
> > > just remove the patsubst and take TEST_GEN_MODS_DIR, which should
> > > be
> > > livepatch/test_modules in this case, but it then returns another
> > > problem:
> > > 
> > > 
> > > make: Entering directory
> > > '/home/mpdesouza/git/linux/tools/testing/selftests'
> > > make[1]: Entering directory
> > > '/home/mpdesouza/git/linux/tools/testing/selftests/livepatch'
> > > make -C test_modules
> > > make[2]: Entering directory
> > > '/home/mpdesouza/git/linux/tools/testing/selftests/livepatch/test
> > > _m
> > > odul
> > > 
> > > es'
> > > make -C /lib/modules/6.5.9-1-default/build modules
> > > KBUILD_EXTMOD=/home/mpdesouza/git/linux/tools/testing/selftests/l
> > > iv
> > > epat
> > > 
> > > ch/test_modules
> > 
> > Nit: There are sometimes strange empty lines between split long
> >      lines. It looks like somehow messed cut&paste.
> 
> Sorry about it. I'll double check the output next time I copy from my
> terminal.
> 
> > 
> > > make[3]: Entering directory '/usr/src/linux-6.5.9-1-
> > > obj/x86_64/default'
> > > make[4]: Entering directory '/tmp/kselftest'
> > > /usr/src/linux-6.5.9-1/Makefile:754: include/config/auto.conf: No
> > > such
> > > file or directory
> > 
> > I see the same. It looks to me like a bug in kernel-devel package.
> > 
> > /usr/src/linux-6.5.9-1/Makefile is from the kernel-devel package
> > for the running kernel. It should try to include auto.conf used
> > for building the running kernel:
> > 
> >   1. auto.conf should be packaged in kernel-devel.
> > 
> >   2. The Makefile from the kernel-devel packages should be able
> >      to find/use auto.conf from the kernel-devel package.
> > 
> > IMHO, this actually helped to find a bug that
> > make -C tools/testing/selftests/livepatch used auto.conf from
> > the git tree while the modules are built against headers
> > for the running kernel.
> > 
> > That said, I wonder why this problem does not happen when building
> > external modules (KMPs). I would expect that they are using
> > the same Makefile from the kernel-devel package.
> > 
> > Maybe the external modules somehow manage to clear "need-config"
> > used by /usr/src/linux-6.5.9-1/Makefile. Maybe we do not need
> > to include it either.
> > 
> > > make[4]: *** [/usr/src/linux-6.5.9-1/Makefile:234: __sub-make]
> > > Error 2
> > > make[4]: Leaving directory '/tmp/kselftest'
> > > make[3]: *** [../../../linux-6.5.9-1/Makefile:234: __sub-make]
> > > Error 2
> > > make[3]: Leaving directory '/usr/src/linux-6.5.9-1-
> > > obj/x86_64/default'
> > > make[2]: *** [Makefile:16: modules] Error 2
> > > make[2]: Leaving directory
> > > '/home/mpdesouza/git/linux/tools/testing/selftests/livepatch/test
> > > _m
> > > odul
> > > 
> > > es'
> > > make[1]: *** [../lib.mk:92: gen_mods_dir] Error 2
> > > make[1]: Leaving directory
> > > '/home/mpdesouza/git/linux/tools/testing/selftests/livepatch'
> > > make: *** [Makefile:180: all] Error 2
> > > make: Leaving directory
> > > '/home/mpdesouza/git/linux/tools/testing/selftests'
> 
> Well, this maybe be indeed a bug in kernel-devel. I added some debug
> messages to make (-dd), and I believe that I understood what's going
> wrong.
> 
> First of all, if we compile an out-of-tree module, like this:
> 
> make -C tools/testing/selftests/livepatch/test_modules
> 
> it goes to /usr/src/linux-6.5.9-1-obj/x86_64/default, and everything
> works. I printed the abs_objtree and it's in fact where it should.
> 
> On like 234 of the toplevel Makefile, ion the __sub-make target, it
> executed the make passed -C to $(abs_objtree), and -f to
> $(abs_srctree). abs_objtree points to /usr/src/linux-6.5.9-1-
> obj/x86_64/default while abs_srctree points to /usr/src/linux-6.5.9-
> 1.
> Everything works.
> 
> But things change whenever we use the O= argument. Its value is
> passed
> to abs_objtree, making the __sub-make to execute is a peculiar way:
> while abs_objtree is /tmp/kselftest, abs_srctree continues to be
> /usr/src/linux-6.5.9-1. That's why the include fails in this case:
> 
> ifdef need-config                                                    
> include include/config/auto.conf                                     
> endif
> 
> As we are calling the include from /tmp/kselftest, and Makefile
> include
> rules try to searching for the file in the directory of it's
> execution[1], it fails. IIUC, all include paths on the toplevel
> makefile should have $(abs_srctree) as prefix, so it could work. But
> as
> Petr said, we don't have the include/config directory packaged in
> kernel-devel.
> 
> I would like to note that this is a problem with out-of-tree module
> building, and not only kselftest related. If we pass O= when building
> a
> module, this will happen.
> 
> For testing purposes, I added the include/{generated,config}
> directories into my /usr/src/linux/include, and added abs_srctree to
> the include mentioned above, and now it's failing with:
> 
> # CC [M] 
> /home/mpdesouza/git/linux/tools/testing/selftests/livepatch/test_modu
> le
> s/test_klp_atomic_replace.o
> gcc -Wp,-
> MMD,/home/mpdesouza/git/linux/tools/testing/selftests/livepatch/test_
> mo
> dules/.test_klp_atomic_replace.o.d -nostdinc -I/usr/src/linux-6.5.9-
> 1/arch/x86/include -I./arch/x86/include/generated -I/usr/src/linux-
> 6.5.9-1/include -I./include -I/usr/src/linux-6.5.9-
> 1/arch/x86/include/uapi -I./arch/x86/include/generated/uapi -
> I/usr/src/linux-6.5.9-1/include/uapi -I./include/generated/uapi -
> include /usr/src/linux-6.5.9-1/include/linux/compiler-version.h -
> include /usr/src/linux-6.5.9-1/include/linux/kconfig.h -include
> /usr/src/linux-6.5.9-1/include/linux/compiler_types.h -D__KERNEL__ -
> Werror -fmacro-prefix-map=/usr/src/linux-6.5.9-1/= -std=gnu11 -
> fshort-
> wchar -funsigned-char -fno-common -fno-PIE -fno-strict-aliasing -Wall
> -
> Wundef -Werror=implicit-function-declaration -Werror=implicit-int -
> Werror=return-type -Werror=strict-prototypes -Wno-format-security -
> Wno-
> trigraphs -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx -fcf-
> protection=branch -fno-jump-tables -m64 -falign-jumps=1 -falign-
> loops=1
> -mno-80387 -mno-fp-ret-in-387 -mpreferred-stack-boundary=3 -mskip-
> rax-
> setup -mtune=generic -mno-red-zone -mcmodel=kernel -Wno-sign-compare
> -
> fno-asynchronous-unwind-tables -mindirect-branch=thunk-extern -
> mindirect-branch-register -mindirect-branch-cs-prefix -mfunction-
> return=thunk-extern -fno-jump-tables -fpatchable-function-entry=16,16
> -
> fno-delete-null-pointer-checks -Wno-frame-address -Wno-format-
> truncation -Wno-format-overflow -Wno-address-of-packed-member -O2 -
> fno-
> allow-store-data-races -Wframe-larger-than=2048 -fstack-protector-
> strong -Wno-main -Wno-unused-but-set-variable -Wno-unused-const-
> variable -Wno-dangling-pointer -ftrivial-auto-var-init=zero -fno-
> stack-
> clash-protection -pg -mrecord-mcount -mfentry -DCC_USING_FENTRY -
> falign-functions=16 -Wvla -Wno-pointer-sign -Wcast-function-type -
> fstrict-flex-arrays=3 -Wno-stringop-truncation -Wno-stringop-overflow
> -
> Wno-restrict -Wno-maybe-uninitialized -Wno-array-bounds -Wno-alloc-
> size-larger-than -Wimplicit-fallthrough=5 -fno-strict-overflow -fno-
> stack-check -fconserve-stack -Werror=date-time -Werror=incompatible-
> pointer-types -Werror=designated-init -Wno-packed-not-aligned -g  -
> DMODULE  -DKBUILD_BASENAME='"test_klp_atomic_replace"' -
> DKBUILD_MODNAME='"test_klp_atomic_replace"' -
> D__KBUILD_MODNAME=kmod_test_klp_atomic_replace -c -o
> /home/mpdesouza/git/linux/tools/testing/selftests/livepatch/test_modu
> le
> s/test_klp_atomic_replace.o
> /home/mpdesouza/git/linux/tools/testing/selftests/livepatch/test_modu
> le
> s/test_klp_atomic_replace.c  
> In file included from /usr/src/linux-6.5.9-
> 1/include/linux/build_bug.h:5,
>                  from /usr/src/linux-6.5.9-
> 1/include/linux/container_of.h:5,
>                  from /usr/src/linux-6.5.9-1/include/linux/list.h:5,
>                  from /usr/src/linux-6.5.9-
> 1/include/linux/module.h:12,
>                  from
> /home/mpdesouza/git/linux/tools/testing/selftests/livepatch/test_modu
> le
> s/test_klp_atomic_replace.c:6:
> /usr/src/linux-6.5.9-1/include/linux/compiler.h:246:10: fatal error:
> asm/rwonce.h: No such file or directory
>   246 | #include <asm/rwonce.h>
>       |          ^~~~~~~~~~~~~~
> compilation terminated.
> 
> Which seems to be missing the asm-generic targets (?). I'm not sure
> what to think now, if this is indeed a bug or if we should adjust
> other
> configurations. As you can see, my lack of Kbuild/Makefile knowledge
> is
> big, but I'm doing my best to understand what's wrong and how I could
> fix it :)
> 
> What do you think about it? Thanks in advance!
> 
> (I'm not sure if the output is messed up again...)
> 
> [1]: https://www.gnu.org/software/make/manual/html_node/Include.html
> 
> > 
> > Best Regards,
> > Petr
>