Re: [GIT PULL] s390 updates for 5.15 merge window

[Nathan Chancellor]

Hi Heiko,

On Mon, Aug 30, 2021 at 03:11:50PM +0200, Heiko Carstens wrote:
> - Enable KCSAN for s390. This comes with a small common code change to fix a
>   compile warning. Acked by Marco Elver:
>   https://lore.kernel.org/r/20210729142811.1309391-1-hca@xxxxxxxxxxxxx/

This caught my eye, as we are boot testing KCSAN + KCSAN_KUNIT_TEST in
our CI [1] for x86_64 so it would be nice to enable this for s390 as
well. However, it does not seem like the unit tests pass when booting up
in QEMU, is this expected or am I doing something wrong? The results and
compiler versions are below (the results are the same), they should both
have the commits that are mentioned in the KCSAN message.

GCC 12.0.0 @ d904008df267cbcc01bd6edf98fa0789fb6e94da

[  131.813482]     not ok 1 - test_basic
[  135.321137]     not ok 2 - test_concurrent_races
[  138.830648]     ok 3 - test_novalue_change
[  142.342562]     not ok 4 - test_novalue_change_exception
[  145.851008]     not ok 5 - test_unknown_origin
[  149.361416]     ok 6 - test_write_write_assume_atomic
[  152.872013]     not ok 7 - test_write_write_struct
[  156.382960]     not ok 8 - test_write_write_struct_part
[  159.890222]     ok 9 - test_read_atomic_write_atomic
[  163.402919]     not ok 10 - test_read_plain_atomic_write
[  166.912931]     not ok 11 - test_read_plain_atomic_rmw
[  170.431915]     not ok 12 - test_zero_size_access
[  173.940959]     ok 13 - test_data_race
[  177.452028]     not ok 14 - test_assert_exclusive_writer
[  180.962840]     not ok 15 - test_assert_exclusive_access
[  184.474686]     not ok 16 - test_assert_exclusive_access_writer
[  187.992282]     not ok 17 - test_assert_exclusive_bits_change
[  191.501869]     ok 18 - test_assert_exclusive_bits_nochange
[  195.013138]     not ok 19 - test_assert_exclusive_writer_scoped
[  199.534212]     not ok 20 - test_assert_exclusive_access_scoped
[  203.053361]     ok 21 - test_jiffies_noreport
[  206.573803]     ok 22 - test_seqlock_noreport
[  210.093508]     ok 23 - test_atomic_builtins
[  210.094014] not ok 1 - kcsan

clang 14.0.0 @ 657bb7262d4a53e903e702d46fdcab57b7085128:

[   10.341427]     not ok 1 - test_basic
[   13.848960]     not ok 2 - test_concurrent_races
[   17.359671]     ok 3 - test_novalue_change
[   20.869202]     not ok 4 - test_novalue_change_exception
[   24.379067]     not ok 5 - test_unknown_origin
[   27.889492]     ok 6 - test_write_write_assume_atomic
[   31.399572]     not ok 7 - test_write_write_struct
[   34.910833]     not ok 8 - test_write_write_struct_part
[   38.419473]     ok 9 - test_read_atomic_write_atomic
[   41.929642]     not ok 10 - test_read_plain_atomic_write
[   45.439644]     not ok 11 - test_read_plain_atomic_rmw
[   48.950048]     not ok 12 - test_zero_size_access
[   52.459026]     ok 13 - test_data_race
[   55.969806]     not ok 14 - test_assert_exclusive_writer
[   59.480436]     not ok 15 - test_assert_exclusive_access
[   62.990164]     not ok 16 - test_assert_exclusive_access_writer
[   66.499199]     not ok 17 - test_assert_exclusive_bits_change
[   70.009481]     ok 18 - test_assert_exclusive_bits_nochange
[   73.522184]     not ok 19 - test_assert_exclusive_writer_scoped
[   78.030448]     not ok 20 - test_assert_exclusive_access_scoped
[   81.539059]     ok 21 - test_jiffies_noreport
[   85.051769]     ok 22 - test_seqlock_noreport
[   88.572048]     ok 23 - test_atomic_builtins
[   88.572279] not ok 1 - kcsan

[1]: https://github.com/ClangBuiltLinux/continuous-integration2

Cheers,
Nathan