mm: don't dereference struct page fields of invalid pages

The VM_BUG_ON() check in move_freepages() checks whether the node id of
a page matches the node id of its zone.  However, it does this before
having checked whether the struct page pointer refers to a valid struct
page to begin with.  This is guaranteed in most cases, but may not be
the case if CONFIG_HOLES_IN_ZONE=y.

So reorder the VM_BUG_ON() with the pfn_valid_within() check.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ard Biesheuvel <[email protected]>
Acked-by: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Hanjun Guo <[email protected]>
Cc: Yisheng Xie <[email protected]>
Cc: Robert Richter <[email protected]>
Cc: James Morse <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions