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Message-ID: <cfecd6ea-8fa3-477f-bd32-4087aefee2af@collabora.com>
Date: Tue, 2 Apr 2024 20:16:25 +0500
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Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>, kernel@collabora.com,
 linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
 linux-kselftest@vger.kernel.org
Subject: Re: [PATCH bpf-next v3] selftests/bpf: Move test_dev_cgroup to
 prog_tests
To: Yonghong Song <yonghong.song@linux.dev>,
 Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>,
 Andrii Nakryiko <andrii@kernel.org>, Martin KaFai Lau
 <martin.lau@linux.dev>, Eduard Zingerman <eddyz87@gmail.com>,
 Song Liu <song@kernel.org>, John Fastabend <john.fastabend@gmail.com>,
 KP Singh <kpsingh@kernel.org>, Stanislav Fomichev <sdf@google.com>,
 Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
 Mykola Lysenko <mykolal@fb.com>, Shuah Khan <shuah@kernel.org>
References: <20240401123455.1377896-1-usama.anjum@collabora.com>
 <92e1cce6-5f26-4a49-86b6-81e1e80d1aaa@linux.dev>
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From: Muhammad Usama Anjum <usama.anjum@collabora.com>
In-Reply-To: <92e1cce6-5f26-4a49-86b6-81e1e80d1aaa@linux.dev>
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Yonghong Song,

Thank you so much for replying. I was missing how to run pipeline manually.
Thanks a ton.

On 4/1/24 11:53 PM, Yonghong Song wrote:
> 
> On 4/1/24 5:34 AM, Muhammad Usama Anjum wrote:
>> Move test_dev_cgroup.c to prog_tests/dev_cgroup.c to be able to run it
>> with test_progs. Replace dev_cgroup.bpf.o with skel header file,
>> dev_cgroup.skel.h and load program from it accourdingly.
>>
>>    ./test_progs -t dev_cgroup
>>    mknod: /tmp/test_dev_cgroup_null: Operation not permitted
>>    64+0 records in
>>    64+0 records out
>>    32768 bytes (33 kB, 32 KiB) copied, 0.000856684 s, 38.2 MB/s
>>    dd: failed to open '/dev/full': Operation not permitted
>>    dd: failed to open '/dev/random': Operation not permitted
>>    #72     test_dev_cgroup:OK
>>    Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
>> Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
>> ---
>> Changes since v2:
>> - Replace test_dev_cgroup with serial_test_dev_cgroup as there is
>>    probability that the test is racing against another cgroup test
>> - Minor changes to the commit message above
>>
>> I've tested the patch with vmtest.sh on bpf-next/for-next and linux
>> next. It is passing on both. Not sure why it was failed on BPFCI.
>> Test run with vmtest.h:
>> sudo LDLIBS=-static PKG_CONFIG='pkg-config --static' ./vmtest.sh
>> ./test_progs -t dev_cgroup
>> ./test_progs -t dev_cgroup
>> mknod: /tmp/test_dev_cgroup_null: Operation not permitted
>> 64+0 records in
>> 64+0 records out
>> 32768 bytes (33 kB, 32 KiB) copied, 0.000403432 s, 81.2 MB/s
>> dd: failed to open '/dev/full': Operation not permitted
>> dd: failed to open '/dev/random': Operation not permitted
>>   #69      dev_cgroup:OK
>> Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
> 
> The CI failure:
> 
> 
> Error: #72 dev_cgroup
> serial_test_dev_cgroup:PASS:skel_open_and_load 0 nsec
> serial_test_dev_cgroup:PASS:cgroup_setup_and_join 0 nsec
> serial_test_dev_cgroup:PASS:bpf_attach 0 nsec
> serial_test_dev_cgroup:PASS:bpf_query 0 nsec
> serial_test_dev_cgroup:PASS:bpf_query 0 nsec
> serial_test_dev_cgroup:PASS:rm 0 nsec
> serial_test_dev_cgroup:PASS:mknod 0 nsec
> serial_test_dev_cgroup:PASS:rm 0 nsec
> serial_test_dev_cgroup:PASS:rm 0 nsec
> serial_test_dev_cgroup:FAIL:mknod unexpected mknod: actual 256 != expected 0
> serial_test_dev_cgroup:PASS:rm 0 nsec
> serial_test_dev_cgroup:PASS:dd 0 nsec
> serial_test_dev_cgroup:PASS:dd 0 nsec
> serial_test_dev_cgroup:PASS:dd 0 nsec
> 
> (cgroup_helpers.c:353: errno: Device or resource busy) umount cgroup2
> 
> The error code 256 means mknod execution has some issues. Maybe you need to
> find specific errno to find out what is going on. I think you can do ci
> on-demanding test to debug.
errno is 2 --> No such file or directory

Locally I'm unable to reproduce it until I don't remove
rm -f /tmp/test_dev_cgroup_zero such that the /tmp/test_dev_cgroup_zero
node is present before test execution. The error code is 256 with errno 2.
I'm debugging by placing system("ls /tmp 1>&2"); to find out which files
are already present in /tmp. But ls's output doesn't appear on the CI logs.

> 
> https://www.kernel.org/doc/Documentation/bpf/bpf_devel_QA.rst
> 

-- 
BR,
Muhammad Usama Anjum