kselftest: mm: fix potential failure for merged VMA in guard-regions

check_vmflag_guard() uses /proc/self/smaps to retrieve the VMA flags, but
this can fail if the mapping is merged with an adjacent VMA.

To avoid this potential failure, first allocate a temporary region with
extra pages at both ends, unmap it, and then map the test region within
the temporary address range, leaving an unmapped page on each side to
prevent VMA merging.

Link: https://lore.kernel.org/20260911142904.1825452-1-yeoreum.yun@arm.com
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>

0 files changed, 0 insertions, 0 deletions