Merge tag 'v3.2.55' into v3.2-rt

This is the 3.2.55 stable release

Conflicts:
	mm/swap.c

4 files changed, 117 insertions, 15 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ddf2128f93fa..3a5aae2d6ee7 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -679,6 +679,23 @@ int PageHuge(struct page *page)
 }
 EXPORT_SYMBOL_GPL(PageHuge);
 
+/*
+ * PageHeadHuge() only returns true for hugetlbfs head page, but not for
+ * normal or transparent huge pages.
+ */
+int PageHeadHuge(struct page *page_head)
+{
+	compound_page_dtor *dtor;
+
+	if (!PageHead(page_head))
+		return 0;
+
+	dtor = get_compound_page_dtor(page_head);
+
+	return dtor == free_huge_page;
+}
+EXPORT_SYMBOL_GPL(PageHeadHuge);
+
 pgoff_t __basepage_index(struct page *page)
 {
 	struct page *page_head = compound_head(page);
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 1b038789a9d6..96c4bcf188b1 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1441,10 +1441,18 @@ static int soft_offline_huge_page(struct page *page, int flags)
 		return ret;
 	}
 done:
-	if (!PageHWPoison(hpage))
-		atomic_long_add(1 << compound_trans_order(hpage), &mce_bad_pages);
-	set_page_hwpoison_huge_page(hpage);
-	dequeue_hwpoisoned_huge_page(hpage);
+	/* overcommit hugetlb page will be freed to buddy */
+	if (PageHuge(hpage)) {
+		if (!PageHWPoison(hpage))
+			atomic_long_add(1 << compound_trans_order(hpage),
+					&mce_bad_pages);
+		set_page_hwpoison_huge_page(hpage);
+		dequeue_hwpoisoned_huge_page(hpage);
+	} else {
+		SetPageHWPoison(page);
+		atomic_long_inc(&mce_bad_pages);
+	}
+
 	/* keep elevated page count for bad page */
 	return ret;
 }
diff --git a/mm/mmap.c b/mm/mmap.c
index dff37a686230..6182c8a4ea38 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1368,7 +1368,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	struct vm_area_struct *vma;
 	unsigned long start_addr;
 
-	if (len > TASK_SIZE)
+	if (len > TASK_SIZE - mmap_min_addr)
 		return -ENOMEM;
 
 	if (flags & MAP_FIXED)
@@ -1377,7 +1377,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	if (addr) {
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
-		if (TASK_SIZE - len >= addr &&
+		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
 		    (!vma || addr + len <= vma->vm_start))
 			return addr;
 	}
@@ -1442,9 +1442,10 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	struct vm_area_struct *vma;
 	struct mm_struct *mm = current->mm;
 	unsigned long addr = addr0;
+	unsigned long low_limit = max(PAGE_SIZE, mmap_min_addr);
 
 	/* requested length too big for entire address space */
-	if (len > TASK_SIZE)
+	if (len > TASK_SIZE - mmap_min_addr)
 		return -ENOMEM;
 
 	if (flags & MAP_FIXED)
@@ -1454,7 +1455,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	if (addr) {
 		addr = PAGE_ALIGN(addr);
 		vma = find_vma(mm, addr);
-		if (TASK_SIZE - len >= addr &&
+		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
 				(!vma || addr + len <= vma->vm_start))
 			return addr;
 	}
@@ -1469,14 +1470,14 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	addr = mm->free_area_cache;
 
 	/* make sure it can fit in the remaining address space */
-	if (addr > len) {
+	if (addr >= low_limit + len) {
 		vma = find_vma(mm, addr-len);
 		if (!vma || addr <= vma->vm_start)
 			/* remember the address as a hint for next time */
 			return (mm->free_area_cache = addr-len);
 	}
 
-	if (mm->mmap_base < len)
+	if (mm->mmap_base < low_limit + len)
 		goto bottomup;
 
 	addr = mm->mmap_base-len;
@@ -1498,7 +1499,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 
 		/* try just below the current vma->vm_start */
 		addr = vma->vm_start-len;
-	} while (len < vma->vm_start);
+	} while (vma->vm_start >= low_limit + len);
 
 bottomup:
 	/*
diff --git a/mm/swap.c b/mm/swap.c
index c77da7af29f9..66a38745054c 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -31,6 +31,7 @@
 #include <linux/backing-dev.h>
 #include <linux/memcontrol.h>
 #include <linux/gfp.h>
+#include <linux/hugetlb.h>
 #include <linux/locallock.h>
 
 #include "internal.h"
@@ -73,7 +74,8 @@ static void __put_compound_page(struct page *page)
 {
 	compound_page_dtor *dtor;
 
-	__page_cache_release(page);
+	if (!PageHuge(page))
+		__page_cache_release(page);
 	dtor = get_compound_page_dtor(page);
 	(*dtor)(page);
 }
@@ -87,6 +89,35 @@ static void put_compound_page(struct page *page)
 		if (likely(page != page_head &&
 			   get_page_unless_zero(page_head))) {
 			unsigned long flags;
+
+			 if (PageHeadHuge(page_head)) {
+				if (likely(PageTail(page))) {
+					/*
+					 * __split_huge_page_refcount
+					 * cannot race here.
+					 */
+					VM_BUG_ON(!PageHead(page_head));
+					atomic_dec(&page->_mapcount);
+					if (put_page_testzero(page_head))
+						VM_BUG_ON(1);
+					if (put_page_testzero(page_head))
+						__put_compound_page(page_head);
+					return;
+				} else {
+					/*
+					 * __split_huge_page_refcount
+					 * run before us, "page" was a
+					 * THP tail. The split
+					 * page_head has been freed
+					 * and reallocated as slab or
+					 * hugetlbfs page of smaller
+					 * order (only possible if
+					 * reallocated as slab on
+					 * x86).
+					 */
+					goto skip_lock;
+				}
+			}
 			/*
 			 * page_head wasn't a dangling pointer but it
 			 * may not be a head page anymore by the time
@@ -98,9 +129,29 @@ static void put_compound_page(struct page *page)
 				/* __split_huge_page_refcount run before us */
 				compound_unlock_irqrestore(page_head, flags);
 				VM_BUG_ON(PageHead(page_head));
-				if (put_page_testzero(page_head))
-					__put_single_page(page_head);
-			out_put_single:
+skip_lock:
+				if (put_page_testzero(page_head)) {
+					/*
+					 * The head page may have been
+					 * freed and reallocated as a
+					 * compound page of smaller
+					 * order and then freed again.
+					 * All we know is that it
+					 * cannot have become: a THP
+					 * page, a compound page of
+					 * higher order, a tail page.
+					 * That is because we still
+					 * hold the refcount of the
+					 * split THP tail and
+					 * page_head was the THP head
+					 * before the split.
+					 */
+					if (PageHead(page_head))
+						__put_compound_page(page_head);
+					else
+						__put_single_page(page_head);
+				}
+out_put_single:
 				if (put_page_testzero(page))
 					__put_single_page(page);
 				return;
@@ -167,6 +218,31 @@ bool __get_page_tail(struct page *page)
 	struct page *page_head = compound_trans_head(page);
 
 	if (likely(page != page_head && get_page_unless_zero(page_head))) {
+		/* Ref to put_compound_page() comment. */
+		if (PageHeadHuge(page_head)) {
+			if (likely(PageTail(page))) {
+				/*
+				 * This is a hugetlbfs
+				 * page. __split_huge_page_refcount
+				 * cannot race here.
+				 */
+				VM_BUG_ON(!PageHead(page_head));
+				__get_page_tail_foll(page, false);
+				return true;
+			} else {
+				/*
+				 * __split_huge_page_refcount run
+				 * before us, "page" was a THP
+				 * tail. The split page_head has been
+				 * freed and reallocated as slab or
+				 * hugetlbfs page of smaller order
+				 * (only possible if reallocated as
+				 * slab on x86).
+				 */
+				put_page(page_head);
+				return false;
+			}
+		}
 		/*
 		 * page_head wasn't a dangling pointer but it
 		 * may not be a head page anymore by the time