commit dd8a67f9a37c74b61e5e050924ceec9ffb4f8c3c
author Zi Yan <zi.yan@cs.rutgers.edu> Thu Nov 02 15:59:47 2017 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> Fri Nov 03 07:39:19 2017 -0700
tree 047993d332418b884aa60f0acf08932842d47701
parent e08b1877452a0055c65f6394163ce5a0fbd720a3

mm/huge_memory.c: deposit page table when copying a PMD migration entry

We need to deposit pre-allocated PTE page table when a PMD migration
entry is copied in copy_huge_pmd().  Otherwise, we will leak the
pre-allocated page and cause a NULL pointer dereference later in
zap_huge_pmd().

The missing counters during PMD migration entry copy process are added
as well.

The bug report is here: https://lkml.org/lkml/2017/10/29/214

Link: http://lkml.kernel.org/r/20171030144636.4836-1-zi.yan@sent.com
Fixes: 84c3fc4e9c563 ("mm: thp: check pmd migration entry in common path")
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>