On 21/08/2026 9:55 am, Catalin Marinas wrote:
> On Thu, Aug 20, 2026 at 04:33:26PM +0100, Muhammad Usama Anjum wrote:
>> The arm64 selftest collection has no Kconfig fragment, so kernels built
>> with the selftest requirements are not guaranteed to provide the support
>> used by the MTE tests.
>>
>> Add a fragment covering the userspace MTE and tagged-address ABIs, KSM
>> and its sysfs interface, explicit HugeTLB mappings and their proc/sysctl
>> interfaces, and tmpfs-backed file mappings.
>>
>> Do not request NUMA solely for the optional KSM merge_across_nodes.
>>
>> Signed-off-by: Muhammad Usama Anjum <[email protected]>
>> ---
>> tools/testing/selftests/arm64/mte/config | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>> create mode 100644 tools/testing/selftests/arm64/mte/config
>>
>> diff --git a/tools/testing/selftests/arm64/mte/config
>> b/tools/testing/selftests/arm64/mte/config
>> new file mode 100644
>> index 0000000000000..8587ce70c294a
>> --- /dev/null
>> +++ b/tools/testing/selftests/arm64/mte/config
>> @@ -0,0 +1,8 @@
>> +CONFIG_ARM64_MTE=y
>> +CONFIG_ARM64_TAGGED_ADDR_ABI=y
>> +CONFIG_HUGETLBFS=y
>> +CONFIG_KSM=y
>> +CONFIG_PROC_FS=y
>> +CONFIG_SYSCTL=y
>
> You may want CONFIG_PROC_SYSCTL.
CONFIG_PROC_SYSCTL no longer exists on the linux-next base used for this
series. It was removed by commit 8d75c338f0bce ("sysctl: remove
CONFIG_PROC_SYSCTL, it just mirrors CONFIG_SYSCTL"), so CONFIG_SYSCTL is
the corresponding requirement in this tree.
>
>> +CONFIG_SYSFS=y
>> +CONFIG_TMPFS=y
>
> These are all covered by defconfig. Are these fragments still necessary?
> Or are they supposed to work on custom configs? If the latter EXPERT may
> be set, hence the PROC_SYSCTL above. You probably also need SHMEM.
The entries were added based on the interfaces exercised by the tests,
rather than only on gaps in arm64 defconfig. The intention was for the
fragment to supply the MTE test requirements when kselftest-merge is used
with a custom configuration.
CONFIG_EXPERT selects DEBUG_KERNEL and exposes many unrelated configuration
options, so the fragment should enable only the concrete options required by
the tests.
--
Thanks,
Usama
