clang: selftests mm pkey_sighandler_tests.c warning duplicate 'inline' declaration specifier [-Wduplicate-decl-specifier]

[Naresh Kamboju <naresh.kamboju@linaro.org>]

The following build warnings were noticed while building selftests/mm
with clang nightly toolchain for arm64 and x86_64 architectures.

Regressions found on arm64 and x86_64
  -  Build/clang-nightly-lkftconfig-kselftest

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

Build regression: selftests mm pkey_sighandler_tests.c warning
duplicate 'inline' declaration specifier [-Wduplicate-decl-specifier]

Build regression: selftests mm mremap_test.c warning pointer
comparison always evaluates to false [-Wtautological-compare]

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

## Build log
make[4]: Entering directory '/builds/linux/tools/testing/selftests/mm'
/bin/sh ./check_config.sh clang --target=aarch64-linux-gnu
-fintegrated-as -Werror=unknown-warning-option
-Werror=ignored-optimization-argument -Werror=option-ignored
-Werror=unused-command-line-argument --target=aarch64-linux-gnu
-fintegrated-as
  CC       cow
  CC       compaction_test
  CC       gup_longterm
  CC       gup_test
  CC       hmm-tests
  CC       hugetlb-madvise
  CC       hugetlb-read-hwpoison
  CC       hugetlb-soft-offline
  CC       hugepage-mmap
  CC       hugepage-mremap
  CC       hugepage-shm
  CC       hugepage-vmemmap
  CC       khugepaged
  CC       madv_populate
  CC       map_fixed_noreplace
  CC       map_hugetlb
  CC       map_populate
  CC       memfd_secret
  CC       migration
  CC       mkdirty
  CC       mlock-random-test
  CC       mlock2-tests
  CC       mrelease_test
  CC       mremap_dontunmap
  CC       mremap_test
mremap_test.c:425:31: warning: pointer comparison always evaluates to
false [-Wtautological-compare]
  425 |                 if (addr + c.dest_alignment < addr) {
      |                                             ^
1 warning generated.
  CC       mseal_test
  CC       on-fault-limit
  CC       pagemap_ioctl
  CC       pfnmap
  CC       thuge-gen
  CC       transhuge-stress
  CC       uffd-stress
  CC       uffd-unit-tests
  CC       uffd-wp-mremap
  CC       split_huge_page_test
  CC       ksm_tests
  CC       ksm_functional_tests
  CC       mdwe_test
  CC       hugetlb_fault_after_madv
  CC       hugetlb_madv_vs_map
  CC       hugetlb_dio
  CC       droppable
  CC       guard-regions
  CC       merge
  CC       protection_keys
  CC       pkey_sighandler_tests
pkey_sighandler_tests.c:44:15: warning: duplicate 'inline' declaration
specifier [-Wduplicate-decl-specifier]
   44 | static inline __always_inline
      |               ^
/usr/lib/gcc-cross/aarch64-linux-gnu/12/../../../../aarch64-linux-gnu/include/sys/cdefs.h:424:26:
note: expanded from macro '__always_inline'
  424 | # define __always_inline __inline __attribute__ ((__always_inline__))
      |                          ^
1 warning generated.
  CC       va_high_addr_switch
  CC       virtual_address_range
  CC       write_to_hugetlbfs

Warning: missing Module.symvers, please have the kernel built first.
page_frag test will be skipped.

make[4]: Leaving directory '/builds/linux/tools/testing/selftests/mm'


## Source
* Kernel version: 6.16.0-rc2
* Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git
* Git sha: 050f8ad7b58d9079455af171ac279c4b9b828c11
* Git describe: next-20250616
* Project details:
https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250616/
* Architectures: arm64, x86_64
* Toolchains: clang nightly
* Kconfigs: selftest/mm/config+defconfig+

## Build arm64
* Build log: https://qa-reports.linaro.org/api/testruns/28765515/log_file/
* Build details:
https://regressions.linaro.org/lkft/linux-next-master/next-20250616/log-parser-build-clang/clang-compiler-pkey_sighandler_tests_c-warning-duplicate-inline-declaration-specifier/
* Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/2ya0viPHafKAe0u89drIv5fcwu2/
* Kernel config:
https://storage.tuxsuite.com/public/linaro/lkft/builds/2ya0viPHafKAe0u89drIv5fcwu2/config


## Steps to reproduce on arm64
 - tuxmake --runtime podman --target-arch arm64 --toolchain clang-20  \
   --kconfig defconfig  \
   --kconfig-add
https://gitlab.com/Linaro/lkft/kernel-fragments/-/raw/main/netdev.config
\
   --kconfig-add
https://gitlab.com/Linaro/lkft/kernel-fragments/-/raw/main/systemd.config
\
   --kconfig-add CONFIG_SYN_COOKIES=y   \
   --kconfig-add CONFIG_SCHEDSTATS=y LLVM=1 LLVM_IAS=1 debugkernel
dtbs dtbs-legacy headers kernel kselftest modules

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