Re: selftests: net/af_unix test_unix_oob [FAILED]

[Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>]

On 8/7/23 22:46, Kuniyuki Iwashima wrote:
> From: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
> Date: Mon, 7 Aug 2023 21:44:41 +0200
>> Hi all,
>>
>> In the kernel 6.5-rc5 build on Ubuntu 22.04 LTS (jammy jellyfish) on a Ryzen 7950 assembled box,
>> vanilla torvalds tree kernel, the test test_unix_oob unexpectedly fails:
>>
>> # selftests: net/af_unix: test_unix_oob
>> # Test 2 failed, sigurg 23 len 63 OOB %
>>
>> It is this code:
>>
>>           /* Test 2:
>>            * Verify that the first OOB is over written by
>>            * the 2nd one and the first OOB is returned as
>>            * part of the read, and sigurg is received.
>>            */
>>           wait_for_data(pfd, POLLIN | POLLPRI);
>>           len = 0;
>>           while (len < 70)
>>                   len = recv(pfd, buf, 1024, MSG_PEEK);
>>           len = read_data(pfd, buf, 1024);
>>           read_oob(pfd, &oob);
>>           if (!signal_recvd || len != 127 || oob != '#') {
>>                   fprintf(stderr, "Test 2 failed, sigurg %d len %d OOB %c\n",
>>                   signal_recvd, len, oob);
>>                   die(1);
>>           }
>>
>> In 6.5-rc4, this test was OK, so it might mean we have a regression?
> 
> Thanks for reporting.
> 
> I confirmed the test doesn't fail on net-next at least, but it's based
> on v6.5-rc4.
> 
>    ---8<---
>    [root@localhost ~]# ./test_unix_oob
>    [root@localhost ~]# echo $?
>    0
>    [root@localhost ~]# uname -r
>    6.5.0-rc4-01192-g66244337512f
>    ---8<---
> 
> I'll check 6.5-rc5 later.

Hi, Kuniyuki,

It seems that there is a new development. I could reproduce the error with the failed test 2
as early as 6.0-rc1. However, the gotcha is that the error appears to be sporadically manifested
(possibly a race)?

I am currently attempting a bisect.

Kind regards,
Mirsad

>> marvin@defiant:~/linux/kernel/linux_torvalds$ grep test_unix_oob ../kselftest-6.5-rc4-1.log
>> /net/af_unix/test_unix_oob
>> # selftests: net/af_unix: test_unix_oob
>> ok 2 selftests: net/af_unix: test_unix_oob
>> marvin@defiant:~/linux/kernel/linux_torvalds$
>>
>> Hope this helps.
>>
>> NOTE: the kernel is vanilla torvalds tree, only "dirty" because the selftests were modified.
>>
>> Kind regards,
>> Mirsad Todorovac