selftests/mm: fix mmap() return value check in run_migration_benchmark

mmap() returns MAP_FAILED on error, not NULL.  The current check uses
!buffer->ptr, which evaluates to false when mmap() fails (since MAP_FAILED
is (void *)-1, not 0), so the error path is never taken.

Link: https://lore.kernel.org/20260512101305.139509-1-lihongfu@kylinos.cn
Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Donet Tom <donettom@linux.ibm.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

0 files changed, 0 insertions, 0 deletions