2024-02-05 06:54:29

by Guenter Roeck

Subject: Kunit test failures with cpumask tests on parisc

Hi,

when running cpumask Kunit tests on parisc/parisc64 in qemu,
I get the following errors.

KTAP version 1
# Subtest: cpumask
# module: cpumask_kunit
1..6
# test_cpumask_weight: EXPECTATION FAILED at lib/cpumask_kunit.c:68
Expected nr_cpu_ids == cpumask_weight(((const struct cpumask *)&__cpu_possible_mask)), but
nr_cpu_ids == 16 (0x10)
cpumask_weight(((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
cpu_possible_mask contains CPUs 0
not ok 1 test_cpumask_weight
# test_cpumask_first: EXPECTATION FAILED at lib/cpumask_kunit.c:79
Expected nr_cpu_ids <= cpumask_first_zero(((const struct cpumask *)&__cpu_possible_mask)), but
nr_cpu_ids == 16 (0x10)
cpumask_first_zero(((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
cpu_possible_mask contains CPUs 0
not ok 2 test_cpumask_first
# test_cpumask_last: EXPECTATION FAILED at lib/cpumask_kunit.c:87
Expected nr_cpu_ids - 1 == cpumask_last(((const struct cpumask *)&__cpu_possible_mask)), but
nr_cpu_ids - 1 == 15 (0xf)
cpumask_last(((const struct cpumask *)&__cpu_possible_mask)) == 0 (0x0)
cpu_possible_mask contains CPUs 0
not ok 3 test_cpumask_last
# test_cpumask_next: EXPECTATION FAILED at lib/cpumask_kunit.c:94
Expected nr_cpu_ids <= cpumask_next_zero(-1, ((const struct cpumask *)&__cpu_possible_mask)), but
nr_cpu_ids == 16 (0x10)
cpumask_next_zero(-1, ((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
cpu_possible_mask contains CPUs 0
not ok 4 test_cpumask_next
ok 5 test_cpumask_iterators
ok 6 test_cpumask_iterators_builtin
# cpumask: pass:2 fail:4 skip:0 total:6
# Totals: pass:2 fail:4 skip:0 total:6
not ok 5 cpumask

It appears that parisc sets __cpu_possible_mask to the number of online CPUs,
which is limited in qemu and doesn't match CONFIG_NR_CPUS. Is this a problem
with the unit test or with the parisc architecture, or does the unit test
simply not apply for parisc ?

Thanks,
Guenter

2024-02-05 09:29:27

by Helge Deller

Subject: Re: Kunit test failures with cpumask tests on parisc

On 2/5/24 07:53, Guenter Roeck wrote:
> when running cpumask Kunit tests on parisc/parisc64 in qemu,
> I get the following errors.
>
> KTAP version 1
> # Subtest: cpumask
> # module: cpumask_kunit
> 1..6
> # test_cpumask_weight: EXPECTATION FAILED at lib/cpumask_kunit.c:68
> Expected nr_cpu_ids == cpumask_weight(((const struct cpumask *)&__cpu_possible_mask)), but
> nr_cpu_ids == 16 (0x10)
> cpumask_weight(((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
> cpu_possible_mask contains CPUs 0
> not ok 1 test_cpumask_weight
> # test_cpumask_first: EXPECTATION FAILED at lib/cpumask_kunit.c:79
> Expected nr_cpu_ids <= cpumask_first_zero(((const struct cpumask *)&__cpu_possible_mask)), but
> nr_cpu_ids == 16 (0x10)
> cpumask_first_zero(((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
> cpu_possible_mask contains CPUs 0
> not ok 2 test_cpumask_first
> # test_cpumask_last: EXPECTATION FAILED at lib/cpumask_kunit.c:87
> Expected nr_cpu_ids - 1 == cpumask_last(((const struct cpumask *)&__cpu_possible_mask)), but
> nr_cpu_ids - 1 == 15 (0xf)
> cpumask_last(((const struct cpumask *)&__cpu_possible_mask)) == 0 (0x0)
> cpu_possible_mask contains CPUs 0
> not ok 3 test_cpumask_last
> # test_cpumask_next: EXPECTATION FAILED at lib/cpumask_kunit.c:94
> Expected nr_cpu_ids <= cpumask_next_zero(-1, ((const struct cpumask *)&__cpu_possible_mask)), but
> nr_cpu_ids == 16 (0x10)
> cpumask_next_zero(-1, ((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
> cpu_possible_mask contains CPUs 0
> not ok 4 test_cpumask_next
> ok 5 test_cpumask_iterators
> ok 6 test_cpumask_iterators_builtin
> # cpumask: pass:2 fail:4 skip:0 total:6
> # Totals: pass:2 fail:4 skip:0 total:6
> not ok 5 cpumask
>
> It appears that parisc sets __cpu_possible_mask to the number of online CPUs,
> which is limited in qemu and doesn't match CONFIG_NR_CPUS. Is this a problem
> with the unit test or with the parisc architecture, or does the unit test
> simply not apply for parisc ?

Thank you for finding and reporting this!
It's a bug (or a misunderstanding) in the parisc kernel.
Reverting commit 0921244f6f4f ("parisc: Only list existing CPUs in cpu_possible_mask")
fixes the KUnit test.

Furthermore the revert fixes the issue that CPU hot-unplugging doesn't
work and which I just was starting to debug:
https://lore.kernel.org/lkml/[email protected]/t/

Helge

2024-02-05 16:10:56

by Guenter Roeck

Subject: Re: Kunit test failures with cpumask tests on parisc

On 2/5/24 01:28, Helge Deller wrote:
> On 2/5/24 07:53, Guenter Roeck wrote:
>> when running cpumask Kunit tests on parisc/parisc64 in qemu,
>> I get the following errors.
>>
>>        KTAP version 1
>>        # Subtest: cpumask
>>        # module: cpumask_kunit
>>        1..6
>>        # test_cpumask_weight: EXPECTATION FAILED at lib/cpumask_kunit.c:68
>>        Expected nr_cpu_ids == cpumask_weight(((const struct cpumask *)&__cpu_possible_mask)), but
>>            nr_cpu_ids == 16 (0x10)
>>            cpumask_weight(((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
>>    cpu_possible_mask contains CPUs 0
>>        not ok 1 test_cpumask_weight
>>        # test_cpumask_first: EXPECTATION FAILED at lib/cpumask_kunit.c:79
>>        Expected nr_cpu_ids <= cpumask_first_zero(((const struct cpumask *)&__cpu_possible_mask)), but
>>            nr_cpu_ids == 16 (0x10)
>>            cpumask_first_zero(((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
>>    cpu_possible_mask contains CPUs 0
>>        not ok 2 test_cpumask_first
>>        # test_cpumask_last: EXPECTATION FAILED at lib/cpumask_kunit.c:87
>>        Expected nr_cpu_ids - 1 == cpumask_last(((const struct cpumask *)&__cpu_possible_mask)), but
>>            nr_cpu_ids - 1 == 15 (0xf)
>>            cpumask_last(((const struct cpumask *)&__cpu_possible_mask)) == 0 (0x0)
>>    cpu_possible_mask contains CPUs 0
>>        not ok 3 test_cpumask_last
>>        # test_cpumask_next: EXPECTATION FAILED at lib/cpumask_kunit.c:94
>>        Expected nr_cpu_ids <= cpumask_next_zero(-1, ((const struct cpumask *)&__cpu_possible_mask)), but
>>            nr_cpu_ids == 16 (0x10)
>>            cpumask_next_zero(-1, ((const struct cpumask *)&__cpu_possible_mask)) == 1 (0x1)
>>    cpu_possible_mask contains CPUs 0
>>        not ok 4 test_cpumask_next
>>        ok 5 test_cpumask_iterators
>>        ok 6 test_cpumask_iterators_builtin
>>    # cpumask: pass:2 fail:4 skip:0 total:6
>>    # Totals: pass:2 fail:4 skip:0 total:6
>>    not ok 5 cpumask
>>
>> It appears that parisc sets __cpu_possible_mask to the number of online CPUs,
>> which is limited in qemu and doesn't match CONFIG_NR_CPUS. Is this a problem
>> with the unit test or with the parisc architecture, or does the unit test
>> simply not apply for parisc ?
>
> Thank you for finding and reporting this!
> It's a bug (or a misunderstanding) in the parisc kernel.
> Reverting commit 0921244f6f4f ("parisc: Only list existing CPUs in cpu_possible_mask")
> fixes the KUnit test.
>
> Furthermore the revert fixes the issue that CPU hot-unplugging doesn't
> work and which I just was starting to debug:
> https://lore.kernel.org/lkml/[email protected]/t/
>

Glad to help, and thanks for the update.

Guenter