Re: [tip:sched/core 7/28] rseq.c:139:37: error: 'AT_RSEQ_ALIGN' undeclared; did you mean 'R_SH_ALIGN'?

[Mathieu Desnoyers]

On 2023-01-17 14:11, Shuah Khan wrote:
> On 1/17/23 10:44, Mathieu Desnoyers wrote:
> > On 2023-01-17 04:06, Ingo Molnar wrote:
> > > * Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > > On 1/16/23 13:18, Mathieu Desnoyers wrote:
> > > > > On 2023-01-16 14:40, kernel test robot wrote:
> > > > > > tree:   
> > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 
> > > > > > sched/core
> > > > > > head:   79ba1e607d68178db7d3fe4f6a4aa38f06805e7b
> > > > > > commit: 03f5c0272d1b59343144e199becc911dae52c37e [7/28] 
> > > > > > selftests/rseq: Use ELF auxiliary vector for extensible rseq
> > > > > > compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
> > > > > > reproduce:
> > > > > >           # 
> > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=03f5c0272d1b59343144e199becc911dae52c37e
> > > > > >           git remote add tip 
> > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
> > > > > >           git fetch --no-tags tip sched/core
> > > > > >           git checkout 03f5c0272d1b59343144e199becc911dae52c37e
> > > > > >           make O=/tmp/kselftest headers
> > > > > >           make O=/tmp/kselftest -C tools/testing/selftests
> > > > > >
> > > > > > If you fix the issue, kindly add following tag where applicable
> > > > > > | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > > > >
> > > > > In order to fix this, I need to change -I../../../../usr/include/ 
> > > > > for $(KHDR_INCLUDES) in tools/testing/selftests/rseq/Makefile
> > > > >
> > > > > I can find 25 odd uses of the same pattern in the kernel selftests. 
> > > > > Should I fix them all in one go ?
> > > >
> > > > kselftest build depends on headers installed in the root directory.
> >
> > By "root directory", do you mean kernel sources root directory or 
> > build output root directory ?
> >
> > > > The main makefile enforces this dependency.
> >
> > How ? I figure that tools/testing/selftests/lib.mk overrides 
> > KHDR_INCLUDES if it is not defined yet:
> >
> > ifeq ($(KHDR_INCLUDES),)
> > KHDR_INCLUDES := -isystem $(top_srcdir)/usr/include
> > endif
> >
> > and selftests makefiles include ../lib.mk.
> >
> > This KHDR_INCLUDES can be modified by O=... when built from the kernel 
> > top level, thus using tools/testing/selftests/Makefile:
> >
> > ifneq ($(KBUILD_OUTPUT),)
> > [...]
> >    KHDR_INCLUDES := -isystem ${abs_objtree}/usr/include
> > else
> > [...]
> >    KHDR_INCLUDES := -isystem ${abs_srctree}/usr/include
> > endif
> >
> > But it's up to the individual selftests to actually use 
> > $(KHDR_INCLUDES). In many cases, they hardcode 
> > -I../../../../usr/include/ which is bogus when the build root (O=...) 
> > differs from the source root.
> >
> >   If this test is being
> > > > built without installing headers by itself, I think the scripts that
> > > > build individual tests have to makes sure headers are installed first.
> >
> > The headers were previously built by "make O=/tmp/kselftest headers", 
> > as it should, it's just that the selftest makefile uses a hardcoded 
> > path that is relative to the source directory, and it appears that 
> > this pattern is repeated all across the selftests.
>
> selftests Makefile used to install headers and there has been a recent
> change to have mani Makefile (root) to install it. As a result individual
> test builds (running make in the test directory) requires header install
> now.
>
> I think the hard-coded includes are a problem and we have to fix them for
> all cases i.e make O=, individual test builds.
>
> If you are still up for it, please send patch.

Sure.

Now that I dig a bit more, we could try using "-nostdinc" to tell the 
compiler not to search the standard system directories, but I've noticed 
that a few selftests depend on userspace library header files found in 
the build environment.

I'm not sure how we should approach this.

Thoughts ?

Thanks,

Mathieu

> thanks,
> -- Shuah

--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com