The selftests arm64 mte build failed on the Linux next-20250703 onwards with clang-20 toolchain. still seen on today's tag next-20250714.

First seen on the tag next-20250703 Good: next-20250702 Bad: next-20250703 (next-20250714)

Regression Analysis: - New regression? Yes - Reproducibility? Yes

Boot regression: next-20250703 check_prctl.c error use of undeclared identifier 'AT_HWCAP3'

Reported-by: Linux Kernel Functional Testing lkft@linaro.org

## Build log make[5]: Entering directory '/builds/linux/tools/testing/selftests/arm64/mte' CC check_buffer_fill CC check_child_memory CC check_gcr_el1_cswitch CC check_hugetlb_options CC check_ksm_options CC check_mmap_options CC check_prctl check_prctl.c:72:17: error: use of undeclared identifier 'AT_HWCAP3' 72 | if ((getauxval(AT_HWCAP3) & hwcap3) != hwcap3) { | ^ 1 error generated. make[5]: *** [../../lib.mk:222: selftest/arm64/mte/check_prctl] Error 1 make[5]: Leaving directory 'tools/testing/selftests/arm64/mte'

## Git Changes git log --oneline next-20250702..next-20250703 tools/testing/selftests/arm64/mte/ 1f488fb91378e kselftest/arm64/mte: Add MTE_STORE_ONLY testcases 391ca7c81b85c kselftest/arm64/mte: Preparation for mte store only test d09674f98cdbf kselftest/arm64/mte: Add mtefar tests on check_mmap_options 64a64e5d12f07 kselftest/arm64/mte: Refactor check_mmap_option test 49cee364c8665 kselftest/arm64/mte: Add verification for address tag in signal handler ed434c6e08132 kselftest/arm64/mte: Add address tag related macro and function 2e3e356560ef5 kselftest/arm64/mte: Check MTE_FAR feature is supported cfafa517c9e65 kselftest/arm64/mte: Register mte signal handler with SA_EXPOSE_TAGBITS

## Source * Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git * Project: https://regressions.linaro.org/lkft/linux-next-master/next-20250714/ * Architectures: arm64 * Toolchains: clang-20 * Kconfigs: defconfig

## Build * Test details: https://regressions.linaro.org/lkft/linux-next-master/next-20250714/kselftes... * Test run: https://regressions.linaro.org/lkft/linux-next-master/next-20250714/testruns... * Test plan: https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/tests/2zrW3Ut4mYW... * Build link: https://storage.tuxsuite.com/public/ampere/ci/builds/2zrZgjFum1wBbTRrsvDGnHC... * Kernel config: https://storage.tuxsuite.com/public/ampere/ci/builds/2zrZgjFum1wBbTRrsvDGnHC...

-- Linaro LKFT https://lkft.linaro.org