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

[Kuniyuki Iwashima]

From: Mirsad Todorovac <mirsad.todorovac@xxxxxxxxxxxx>
Date: Mon, 22 May 2023 17:32:11 +0200
> Hi,
> 
> On vanilla AlmaLinux 8.7 (CentOS fork) selftests/net/af_unix/diag_uid.c doesn't
> compile out of the box, giving the errors:
> 
> make[2]: Entering directory '/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/net/af_unix'
> gcc     diag_uid.c  -o /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/net/af_unix/diag_uid
> diag_uid.c:36:16: error: ‘UDIAG_SHOW_UID’ undeclared here (not in a function); did you mean ‘UDIAG_SHOW_VFS’?
>    .udiag_show = UDIAG_SHOW_UID
>                  ^~~~~~~~~~~~~~
>                  UDIAG_SHOW_VFS
> In file included from diag_uid.c:17:
> diag_uid.c: In function ‘render_response’:
> diag_uid.c:128:28: error: ‘UNIX_DIAG_UID’ undeclared (first use in this function); did you mean ‘UNIX_DIAG_VFS’?
>    ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
>                              ^~~~~~~~~~~~~
> ../../kselftest_harness.h:707:13: note: in definition of macro ‘__EXPECT’
>    __typeof__(_seen) __seen = (_seen); \
>               ^~~~~
> diag_uid.c:128:2: note: in expansion of macro ‘ASSERT_EQ’
>    ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
>    ^~~~~~~~~
> diag_uid.c:128:28: note: each undeclared identifier is reported only once for each function it appears in
>    ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
>                              ^~~~~~~~~~~~~
> ../../kselftest_harness.h:707:13: note: in definition of macro ‘__EXPECT’
>    __typeof__(_seen) __seen = (_seen); \
>               ^~~~~
> diag_uid.c:128:2: note: in expansion of macro ‘ASSERT_EQ’
>    ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
>    ^~~~~~~~~
> make[2]: *** [../../lib.mk:147: /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/net/af_unix/diag_uid] Error 1
> 
> The correct value is in <uapi/linux/unix_diag.h>:
> 
> include/uapi/linux/unix_diag.h:23:#define UDIAG_SHOW_UID		0x00000040	/* show socket's UID */
> 
> The fix is as follows:
> 
> ---
>   tools/testing/selftests/net/af_unix/diag_uid.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/tools/testing/selftests/net/af_unix/diag_uid.c b/tools/testing/selftests/net/af_unix/diag_uid.c
> index 5b88f7129fea..66d75b646d35 100644
> --- a/tools/testing/selftests/net/af_unix/diag_uid.c
> +++ b/tools/testing/selftests/net/af_unix/diag_uid.c
> @@ -16,6 +16,10 @@
> 
>   #include "../../kselftest_harness.h"
> 
> +#ifndef UDIAG_SHOW_UID
> +#define UDIAG_SHOW_UID         0x00000040      /* show socket's UID */
> +#endif
> +
>   FIXTURE(diag_uid)
>   {
>          int netlink_fd;
> 
> --
> 
> However, this patch reveals another undefined value:
> 
> make[2]: Entering directory '/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/net/af_unix'
> gcc     diag_uid.c  -o /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/net/af_unix/diag_uid
> In file included from diag_uid.c:17:
> diag_uid.c: In function ‘render_response’:
> diag_uid.c:132:28: error: ‘UNIX_DIAG_UID’ undeclared (first use in this function); did you mean ‘UNIX_DIAG_VFS’?
>    ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
>                              ^~~~~~~~~~~~~
> ../../kselftest_harness.h:707:13: note: in definition of macro ‘__EXPECT’
>    __typeof__(_seen) __seen = (_seen); \
>               ^~~~~
> diag_uid.c:132:2: note: in expansion of macro ‘ASSERT_EQ’
>    ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
>    ^~~~~~~~~
> diag_uid.c:132:28: note: each undeclared identifier is reported only once for each function it appears in
>    ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
>                              ^~~~~~~~~~~~~
> ../../kselftest_harness.h:707:13: note: in definition of macro ‘__EXPECT’
>    __typeof__(_seen) __seen = (_seen); \
>               ^~~~~
> diag_uid.c:132:2: note: in expansion of macro ‘ASSERT_EQ’
>    ASSERT_EQ(attr->rta_type, UNIX_DIAG_UID);
>    ^~~~~~~~~
> make[2]: *** [../../lib.mk:147: /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/net/af_unix/diag_uid] Error 1
> 
> Apparently, AlmaLinux 8.7 lacks this enum UNIX_DIAG_UID:
> 
> diff -u /usr/include/linux/unix_diag.h include/uapi/linux/unix_diag.h
> --- /usr/include/linux/unix_diag.h	2023-05-16 13:47:51.000000000 +0200
> +++ include/uapi/linux/unix_diag.h	2022-10-12 07:35:58.253481367 +0200
> @@ -20,6 +20,7 @@
>   #define UDIAG_SHOW_ICONS	0x00000008	/* show pending connections */
>   #define UDIAG_SHOW_RQLEN	0x00000010	/* show skb receive queue len */
>   #define UDIAG_SHOW_MEMINFO	0x00000020	/* show memory info of a socket */
> +#define UDIAG_SHOW_UID		0x00000040	/* show socket's UID */
> 
>   struct unix_diag_msg {
>   	__u8	udiag_family;
> @@ -40,6 +41,7 @@
>   	UNIX_DIAG_RQLEN,
>   	UNIX_DIAG_MEMINFO,
>   	UNIX_DIAG_SHUTDOWN,
> +	UNIX_DIAG_UID,
> 
>   	__UNIX_DIAG_MAX,
>   };
> 
> Now, this is a change in enums and there doesn't seem to an easy way out
> here. (I think I saw an example, but I cannot recall which thread. I will do
> more research.)
> 
> When I included
> 
> # gcc -I ../../../../include diag_uid.c
> 
> I've got the following error:
> 
> [marvin@pc-mtodorov linux_torvalds]$ cd tools/testing/selftests/net/af_unix/
> [marvin@pc-mtodorov af_unix]$ gcc  -I ../../../../../include   diag_uid.c  -o 
> /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/net/af_unix/diag_uid
> 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>
>            ^~~~~~~~~~~~~~
> compilation terminated.
> [marvin@pc-mtodorov af_unix]$
> 
> At this point I gave up, as it would be an overkill to change kernel system
> header to make a test pass, and this probably wouldn't be accepted upsteam?
> 
> Hope this helps. (If we still want to build on CentOS/AlmaLinux/Rocky 8?)

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


> 
> Best regards,
> 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