Merge branch 'akpm' (patches from Andrew)

Merge fixes from Andrew Morton:
 "14 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  byteswap: try to avoid __builtin_constant_p gcc bug
  lib/stackdepot: avoid to return 0 handle
  mm: fix kcompactd hang during memory offlining
  modpost: fix module autoloading for OF devices with generic compatible property
  proc: prevent accessing /proc/<PID>/environ until it's ready
  mm/zswap: provide unique zpool name
  mm: thp: kvm: fix memory corruption in KVM with THP enabled
  MAINTAINERS: fix Rajendra Nayak's address
  mm, cma: prevent nr_isolated_* counters from going negative
  mm: update min_free_kbytes from khugepaged after core initialization
  huge pagecache: mmap_sem is unlocked when truncation splits pmd
  rapidio/mport_cdev: fix uapi type definitions
  mm: memcontrol: let v2 cgroups follow changes in system swappiness
  mm: thp: correct split_huge_pages file permission

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 9e0b0315a724..53ad6c0831ae 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -42,12 +42,14 @@
 
 #define DEPOT_STACK_BITS (sizeof(depot_stack_handle_t) * 8)
 
+#define STACK_ALLOC_NULL_PROTECTION_BITS 1
 #define STACK_ALLOC_ORDER 2 /* 'Slab' size order for stack depot, 4 pages */
 #define STACK_ALLOC_SIZE (1LL << (PAGE_SHIFT + STACK_ALLOC_ORDER))
 #define STACK_ALLOC_ALIGN 4
 #define STACK_ALLOC_OFFSET_BITS (STACK_ALLOC_ORDER + PAGE_SHIFT - \
 					STACK_ALLOC_ALIGN)
-#define STACK_ALLOC_INDEX_BITS (DEPOT_STACK_BITS - STACK_ALLOC_OFFSET_BITS)
+#define STACK_ALLOC_INDEX_BITS (DEPOT_STACK_BITS - \
+		STACK_ALLOC_NULL_PROTECTION_BITS - STACK_ALLOC_OFFSET_BITS)
 #define STACK_ALLOC_SLABS_CAP 1024
 #define STACK_ALLOC_MAX_SLABS \
 	(((1LL << (STACK_ALLOC_INDEX_BITS)) < STACK_ALLOC_SLABS_CAP) ? \
@@ -59,6 +61,7 @@ union handle_parts {
 	struct {
 		u32 slabindex : STACK_ALLOC_INDEX_BITS;
 		u32 offset : STACK_ALLOC_OFFSET_BITS;
+		u32 valid : STACK_ALLOC_NULL_PROTECTION_BITS;
 	};
 };
 
@@ -136,6 +139,7 @@ static struct stack_record *depot_alloc_stack(unsigned long *entries, int size,
 	stack->size = size;
 	stack->handle.slabindex = depot_index;
 	stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN;
+	stack->handle.valid = 1;
 	memcpy(stack->entries, entries, size * sizeof(unsigned long));
 	depot_offset += required_size;