mm: expose abnormal new_pte during move_ptes

When executing move_ptes, the new_pte must be NULL, otherwise it will be
overwritten by the old_pte, and cause the abnormal new_pte to be leaked. 
In order to make this problem to be more explicit, let's add WARN_ON_ONCE
when new_pte is not NULL.

[[email protected]: s/WARN_ON_ONCE/VM_WARN_ON_ONCE/]
Link: https://lkml.kernel.org/r/[email protected]
Suggested-by: Oleg Nesterov <[email protected]>
Signed-off-by: Pu Lehui <[email protected]>
Reviewed-by: Lorenzo Stoakes <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Liam Howlett <[email protected]>
Cc: "Masami Hiramatsu (Google)" <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions