Re: [BUG] selftests: af_unix: unix:diag.c does not compile on AlmaLinux 8.7

[Mirsad Todorovac]

Hi,

On 5/22/23 20:26, Kuniyuki Iwashima wrote:
> > > I launched AlmaLinux/RockyLinux 8.7 and 9.2 with images listed in the pages
> > > below.
> > >
> > >     https://wiki.almalinux.org/cloud/AWS.html#community-amis
> > >     https://rockylinux.org/cloud-images/
> > >
> > > The kernel versions in each image were :
> > >
> > >     8.7:
> > >     Alma  : 4.18.0-425.3.1.el8.x86_64
> > >     Rocky : 4.18.0-425.10.1.el8_7.x86_64
> > >
> > >     9.2:
> > >     Alma  : 5.14.0-284.11.1.el9_2.x86_64
> > >     Rocky : 5.14.0-284.11.1.el9_2.x86_64
> > >
> > > So, this is not a bug.  It's just because v4.18 does not support
> > > UNIX_DIAG_UID, which was introduced in v5.3.
> > >
> > > You should install 5.3+ kernel if you want to build the test.
> > >
> > > Thanks,
> > > Kuniyuki
> >
> > Hi, Kuniyuki,
> >
> > Good point. However, newer kernel won't save me from old /usr/include
> > headers, will it?
>
> Sorry, I meant kernel and kernel-headers package that should be
> updated along with kernel.
>
> You should use proper header files that match to the actual kernel
> version running on the machine.
>
>
> > I was actually testing the 6.4-rc3 on AlmaLinux 8.7, as it is my only
> > RHEL-based box ...
> >
> > What would then be the right action?
>
> make headers_install ?

I would rather not to. For the installation to remain manageable,
preferably I'd have a kernel-devel RPM built.

> > If it was a #define instead of enum, I'd probably work around and
> > exclude the test that doesn't fit the kernel, or the system call
> > would return -EINVAL?
> >
> > Including from the includes that came with the kernel might be
> > a solution:
> >
> > ../../../../../include/uapi/linux/unix_diag.h:44:	UNIX_DIAG_UID,
> >
> > Alas, when I try to include, I get these ugly errors:
> >
> > [marvin@pc-mtodorov af_unix]$ gcc -I ../../../../../include/ diag_uid.c
> > In file included from ../../../../../include/linux/build_bug.h:5,
> >                    from ../../../../../include/linux/bits.h:21,
> >                    from ../../../../../include/linux/capability.h:18,
> >                    from ../../../../../include/linux/netlink.h:6,
> >                    from diag_uid.c:8:
> > ../../../../../include/linux/compiler.h:246:10: fatal error:
> > asm/rwonce.h: No such file or directory
> >    #include <asm/rwonce.h>
> >             ^~~~~~~~~~~~~~
>
> FWIW, this is provided by kernel-devel package.

Actually, what is provided is essentially the same as before:

[root@pc-mtodorov kernel]# rpm -q --fileprovide kernel-devel-6.3.3 | grep rwonce.h
/usr/src/kernels/6.3.3-100.fc37.x86_64/arch/x86/include/generated/asm/rwonce.h	
/usr/src/kernels/6.3.3-100.fc37.x86_64/include/asm-generic/rwonce.h	
[root@pc-mtodorov kernel]#

> > compilation terminated.
> > [marvin@pc-mtodorov af_unix]$ vi +246
> > ../../../../../include/linux/compiler.h
> > [marvin@pc-mtodorov af_unix]$ find ../../../../../include -name rwonce.h
> > ../../../../../include/asm-generic/rwonce.h
> > [marvin@pc-mtodorov af_unix]$
> >
> > Minimum reproducer is:
> >
> > [marvin@pc-mtodorov af_unix]$ gcc -I ../../../../../include/ reproducer.c
> > In file included from ../../../../../include/linux/build_bug.h:5,
> >                    from ../../../../../include/linux/bits.h:21,
> >                    from ../../../../../include/linux/capability.h:18,
> >                    from ../../../../../include/linux/netlink.h:6,
> >                    from reproducer.c:5:
> > ../../../../../include/linux/compiler.h:246:10: fatal error:
> > asm/rwonce.h: No such file or directory
> >    #include <asm/rwonce.h>
> >             ^~~~~~~~~~~~~~
> > compilation terminated.
> > [marvin@pc-mtodorov af_unix]$
> >
> > [marvin@pc-mtodorov af_unix]$ nl reproducer.c
> >
> >        1	#define _GNU_SOURCE
> >        2	#include <linux/netlink.h>
> >
> > [marvin@pc-mtodorov af_unix]$
> >
> > Am I doing something very stupid right now, for actually I see
> >
> > #include <asm/rwonce.h>
> >
> > in "include/linux/compiler.h" 248L, 7843C
> >
> > while actual rwonce.h is in <asm-generic/rwonce.h>
> >
> > [marvin@pc-mtodorov af_unix]$ find ../../../../../include -name rwonce.h
> > ../../../../../include/asm-generic/rwonce.h
> > [marvin@pc-mtodorov af_unix]$
> >
> > I must be doing something wrong, for I see that the kernel compiled
> > despite not having include/asm ?
> >
> > When looking at the invocations of rwonce.h in the kernel, they seem to
> > be equally spread between <asm-generic/rwonce.h> and <asm/rwonce.h> :
> >
> > [marvin@pc-mtodorov af_unix]$ grep --include="*.[ch]" -n -w rwonce.h -r ../../../../.. 2> /dev/null | less
> > ../../../../../arch/alpha/include/asm/rwonce.h:33:#include <asm-generic/rwonce.h>
> > ../../../../../arch/arm64/include/asm/rwonce.h:71:#include <asm-generic/rwonce.h>
> > ../../../../../arch/arm64/kvm/hyp/include/nvhe/spinlock.h:18:#include <asm/rwonce.h>
> > ../../../../../arch/s390/include/asm/rwonce.h:29:#include <asm-generic/rwonce.h>
> > ../../../../../arch/x86/include/generated/asm/rwonce.h:1:#include <asm-generic/rwonce.h>
> > ../../../../../include/asm-generic/barrier.h:18:#include <asm/rwonce.h>
> > ../../../../../include/kunit/test.h:29:#include <asm/rwonce.h>
> > ../../../../../include/linux/compiler.h:246:#include <asm/rwonce.h>
> >
> > I figured out I must be doing something wrong or the kernel otherwise
> > would not build for me.
> >
> > Eventually, the UNIX_DIAG_UID enum is used in only one place:
> >
> >           ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
> >
> > That particular test should fail in case of kernel older than 5.3.
>
> We don't expect it to be run on older kernels in the first place.

Certainly.

> > However, I fell into a terrible mess where one thing breaks the other.
> >
> > I can't seem to make this work.
> >
> > Thanks,
> > Mirsad

--
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu

System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia