Re: [BUG] selftests: af_unix: unix:diag.c does not compile on AlmaLinux 8.7
From: Mirsad Goran Todorovac
Date: Mon May 22 2023 - 14:01:33 EST
On 5/22/23 18:28, Kuniyuki Iwashima wrote:
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
Hi, Kuniyuki,
Good point. However, newer kernel won't save me from old /usr/include
headers, will it?
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?
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>
^~~~~~~~~~~~~~
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.
However, I fell into a terrible mess where one thing breaks the other.
I can't seem to make this work.
Thanks,
Mirsad