Merge branch 'akpm'

* akpm:
  mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGES block during isolation for migration
  readahead: fix pipeline break caused by block plug
  kprobes: fix a memory leak in function pre_handler_kretprobe()
  drivers/tty/vt/vt_ioctl.c: fix KDFONTOP 32bit compatibility layer
  lkdtm: avoid calling lkdtm_do_action() with spinlock held
  mm/filemap_xip.c: fix race condition in xip_file_fault()
  mm/memcontrol.c: fix warning with CONFIG_NUMA=n
  avr32: select generic atomic64_t support
  mm: postpone migrated page mapping reset
  xtensa: fix memscan()
  MAINTAINERS: update lguest F: patterns
  MAINTAINERS: remove staging sections
  MAINTAINERS: remove iMX5 section
  MAINTAINERS: update partitions block F: patterns

1 files changed, 13 insertions, 0 deletions

diff --git a/mm/compaction.c b/mm/compaction.c
index 71a58f6..bd939a5 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -313,6 +313,19 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 		} else if (!locked)
 			spin_lock_irq(&zone->lru_lock);
 
+		/*
+		 * migrate_pfn does not necessarily start aligned to a
+		 * pageblock. Ensure that pfn_valid is called when moving
+		 * into a new MAX_ORDER_NR_PAGES range in case of large
+		 * memory holes within the zone
+		 */
+		if ((low_pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) {
+			if (!pfn_valid(low_pfn)) {
+				low_pfn += MAX_ORDER_NR_PAGES - 1;
+				continue;
+			}
+		}
+
 		if (!pfn_valid_within(low_pfn))
 			continue;
 		nr_scanned++;