Re: [PATCH 5.15 0/6] Backporting for 5.15 test_verifier failed

[Luiz Capitulino <luizcap@amazon.com>]

On 2023-08-04 11:30, Pu Lehui wrote:

> 
> 
> 
> Hi Luiz,
> 
> My local 5.15 environment is a little bit weird, could you help me to
> test it?

I'll give this a try, but unfortunately I'm not sure I'll be able to
get back to you before mid next week.

- Luiz

> 
> On 2023/8/4 23:24, Pu Lehui wrote:
>> Luiz Capitulino reported the test_verifier test failed:
>> "precise: ST insn causing spi > allocated_stack".
>> And it was introduced by the following upstream commit:
>> ecdf985d7615 ("bpf: track immediate values written to stack by BPF_ST instruction")
>>
>> Eduard's investigation [4] shows that test failure is not a bug, but a
>> difference in BPF verifier behavior between upstream, where commits
>> [1,2,3] by Andrii are present, and 5.15, where these commits are absent.
>>
>> Backporting strategy is consistent with Eduard in kernel version 6.1 [5],
>> but with some conflicts in patch #1, #4 and #6 due to the bpf of 5.15
>> doesn't support more features.
>>
>> Commits of Andrii:
>> [1] be2ef8161572 ("bpf: allow precision tracking for programs with subprogs")
>> [2] f63181b6ae79 ("bpf: stop setting precise in current state")
>> [3] 7a830b53c17b ("bpf: aggressively forget precise markings during state checkpointing")
>>
>> Links:
>> [4] https://lore.kernel.org/stable/c9b10a8a551edafdfec855fbd35757c6238ad258.camel@gmail.com/
>> [5] https://lore.kernel.org/all/20230724124223.1176479-2-eddyz87@gmail.com/
>>
>> Andrii Nakryiko (4):
>>    bpf: allow precision tracking for programs with subprogs
>>    bpf: stop setting precise in current state
>>    bpf: aggressively forget precise markings during state checkpointing
>>    selftests/bpf: make test_align selftest more robust
>>
>> Ilya Leoshkevich (1):
>>    selftests/bpf: Fix sk_assign on s390x
>>
>> Yonghong Song (1):
>>    selftests/bpf: Workaround verification failure for
>>      fexit_bpf2bpf/func_replace_return_code
>>
>>   kernel/bpf/verifier.c                         | 199 ++++++++++++++++--
>>   .../testing/selftests/bpf/prog_tests/align.c  |  36 ++--
>>   .../selftests/bpf/prog_tests/sk_assign.c      |  25 ++-
>>   .../selftests/bpf/progs/connect4_prog.c       |   2 +-
>>   .../selftests/bpf/progs/test_sk_assign.c      |  11 +
>>   .../bpf/progs/test_sk_assign_libbpf.c         |   3 +
>>   6 files changed, 243 insertions(+), 33 deletions(-)
>>   create mode 100644 tools/testing/selftests/bpf/progs/test_sk_assign_libbpf.c
>>