Messages in this thread | | | Date | Mon, 5 Feb 2024 10:28:27 +0100 | Subject | Re: Kunit test failures with cpumask tests on parisc | From | Helge Deller <> |
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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/Zb0mbHlIud_bqftx@slm.duckdns.org/t/
Helge
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