selftests/mm: fix clone cleartid race in pkey sighandler tests

Passing a stack-local child_pid to clone() with CLONE_CHILD_CLEARTID is
unsafe: the kernel clears that address when the child exits, which may
happen after the test function has returned and the stack slot has been
reused.

Neither testcase uses the settid/cleartid pointers for synchronization.

Drop CLONE_PARENT_SETTID and CLONE_CHILD_CLEARTID and pass NULL for the
clone tid arguments.  Wait for the clone child to exit via tkill in
test_sigsegv_handler_with_different_pkey_for_stack(), matching
test_pkru_sigreturn(), so the detached thread cannot overlap with the next
testcase.

Link: https://lore.kernel.org/20260706081600.3570203-7-lihongfu@kylinos.cn
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Cc: David Hildenbrand <david@kernel.org>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Keith Lucas <keith.lucas@oracle.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Liam R. Howlett (Oracle) <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Ross Zwisler <zwisler@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Yury Khrustalev <yury.khrustalev@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions