Merge branch 'akpm' (patches from Andrew)

Merge fixes from Andrew Morton:
 "11 fixes.

  The presence of 'thp: reduce indentation level in change_huge_pmd()'
  is unfortunate. But the patchset had been decently reviewed and tested
  before we decided it was needed in -stable and I felt it best not to
  churn things at the last minute"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mailmap: add Martin Kepplinger's email
  zsmalloc: expand class bit
  zram: do not use copy_page with non-page aligned address
  zram: fix operator precedence to get offset
  hugetlbfs: fix offset overflow in hugetlbfs mmap
  thp: fix MADV_DONTNEED vs clear soft dirty race
  thp: fix MADV_DONTNEED vs. MADV_FREE race
  mm: drop unused pmdp_huge_get_and_clear_notify()
  thp: fix MADV_DONTNEED vs. numa balancing race
  thp: reduce indentation level in change_huge_pmd()
  z3fold: fix page locking in z3fold_alloc()

.mailmap

@@ -99,6 +99,8 @@ Linas Vepstas <linas@austin.ibm.com>
 Linus Lüssing <linus.luessing@c0d3.blue> <linus.luessing@web.de>
 Linus Lüssing <linus.luessing@c0d3.blue> <linus.luessing@ascom.ch>
 Mark Brown <broonie@sirena.org.uk>
+Martin Kepplinger <martink@posteo.de> <martin.kepplinger@theobroma-systems.com>
+Martin Kepplinger <martink@posteo.de> <martin.kepplinger@ginzinger.com>
 Matthieu CASTET <castet.matthieu@free.fr>
 Mauro Carvalho Chehab <mchehab@kernel.org> <mchehab@brturbo.com.br>
 Mauro Carvalho Chehab <mchehab@kernel.org> <maurochehab@gmail.com>

drivers/block/zram/zram_drv.c

@@ -523,7 +523,7 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
 
 	cmem = zs_map_object(meta->mem_pool, handle, ZS_MM_RO);
 	if (size == PAGE_SIZE) {
-		copy_page(mem, cmem);
+		memcpy(mem, cmem, PAGE_SIZE);
 	} else {
 		struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp);
 
@@ -717,7 +717,7 @@ compress_again:
 
 	if ((clen == PAGE_SIZE) && !is_partial_io(bvec)) {
 		src = kmap_atomic(page);
-		copy_page(cmem, src);
+		memcpy(cmem, src, PAGE_SIZE);
 		kunmap_atomic(src);
 	} else {
 		memcpy(cmem, src, clen);
@@ -928,7 +928,7 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,
 	}
 
 	index = sector >> SECTORS_PER_PAGE_SHIFT;
-	offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT;
+	offset = (sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
 
 	bv.bv_page = page;
 	bv.bv_len = PAGE_SIZE;

fs/hugetlbfs/inode.c

@@ -136,17 +136,26 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 	vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
 	vma->vm_ops = &hugetlb_vm_ops;
 
+	/*
+	 * Offset passed to mmap (before page shift) could have been
+	 * negative when represented as a (l)off_t.
+	 */
+	if (((loff_t)vma->vm_pgoff << PAGE_SHIFT) < 0)
+		return -EINVAL;
+
 	if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 		return -EINVAL;
 
 	vma_len = (loff_t)(vma->vm_end - vma->vm_start);
+	len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+	/* check for overflow */
+	if (len < vma_len)
+		return -EINVAL;
 
 	inode_lock(inode);
 	file_accessed(file);
 
 	ret = -ENOMEM;
-	len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
-
 	if (hugetlb_reserve_pages(inode,
 				vma->vm_pgoff >> huge_page_order(h),
 				len >> huge_page_shift(h), vma,
@@ -155,7 +164,7 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 
 	ret = 0;
 	if (vma->vm_flags & VM_WRITE && inode->i_size < len)
-		inode->i_size = len;
+		i_size_write(inode, len);
 out:
 	inode_unlock(inode);
 

fs/proc/task_mmu.c

@@ -900,7 +900,14 @@ static inline void clear_soft_dirty(struct vm_area_struct *vma,
 static inline void clear_soft_dirty_pmd(struct vm_area_struct *vma,
 		unsigned long addr, pmd_t *pmdp)
 {
-	pmd_t pmd = pmdp_huge_get_and_clear(vma->vm_mm, addr, pmdp);
+	pmd_t pmd = *pmdp;
+
+	/* See comment in change_huge_pmd() */
+	pmdp_invalidate(vma, addr, pmdp);
+	if (pmd_dirty(*pmdp))
+		pmd = pmd_mkdirty(pmd);
+	if (pmd_young(*pmdp))
+		pmd = pmd_mkyoung(pmd);
 
 	pmd = pmd_wrprotect(pmd);
 	pmd = pmd_clear_soft_dirty(pmd);

include/linux/mmu_notifier.h

@@ -394,18 +394,6 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
 	___pud;								\
 })
 
-#define pmdp_huge_get_and_clear_notify(__mm, __haddr, __pmd)		\
-({									\
-	unsigned long ___haddr = __haddr & HPAGE_PMD_MASK;		\
-	pmd_t ___pmd;							\
-									\
-	___pmd = pmdp_huge_get_and_clear(__mm, __haddr, __pmd);		\
-	mmu_notifier_invalidate_range(__mm, ___haddr,			\
-				      ___haddr + HPAGE_PMD_SIZE);	\
-									\
-	___pmd;								\
-})
-
 /*
  * set_pte_at_notify() sets the pte _after_ running the notifier.
  * This is safe to start by updating the secondary MMUs, because the primary MMU
@@ -489,7 +477,6 @@ static inline void mmu_notifier_mm_destroy(struct mm_struct *mm)
 #define	ptep_clear_flush_notify ptep_clear_flush
 #define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush
 #define pudp_huge_clear_flush_notify pudp_huge_clear_flush
-#define pmdp_huge_get_and_clear_notify pmdp_huge_get_and_clear
 #define set_pte_at_notify set_pte_at
 
 #endif /* CONFIG_MMU_NOTIFIER */

mm/huge_memory.c

@@ -1568,8 +1568,7 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		deactivate_page(page);
 
 	if (pmd_young(orig_pmd) || pmd_dirty(orig_pmd)) {
-		orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
-			tlb->fullmm);
+		pmdp_invalidate(vma, addr, pmd);
 		orig_pmd = pmd_mkold(orig_pmd);
 		orig_pmd = pmd_mkclean(orig_pmd);
 
@@ -1724,37 +1723,69 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 {
 	struct mm_struct *mm = vma->vm_mm;
 	spinlock_t *ptl;
-	int ret = 0;
+	pmd_t entry;
+	bool preserve_write;
+	int ret;
 
 	ptl = __pmd_trans_huge_lock(pmd, vma);
-	if (ptl) {
-		pmd_t entry;
-		bool preserve_write = prot_numa && pmd_write(*pmd);
-		ret = 1;
+	if (!ptl)
+		return 0;
 
-		/*
-		 * Avoid trapping faults against the zero page. The read-only
-		 * data is likely to be read-cached on the local CPU and
-		 * local/remote hits to the zero page are not interesting.
-		 */
-		if (prot_numa && is_huge_zero_pmd(*pmd)) {
-			spin_unlock(ptl);
-			return ret;
-		}
+	preserve_write = prot_numa && pmd_write(*pmd);
+	ret = 1;
 
-		if (!prot_numa || !pmd_protnone(*pmd)) {
-			entry = pmdp_huge_get_and_clear_notify(mm, addr, pmd);
-			entry = pmd_modify(entry, newprot);
-			if (preserve_write)
-				entry = pmd_mk_savedwrite(entry);
-			ret = HPAGE_PMD_NR;
-			set_pmd_at(mm, addr, pmd, entry);
-			BUG_ON(vma_is_anonymous(vma) && !preserve_write &&
-					pmd_write(entry));
-		}
-		spin_unlock(ptl);
-	}
+	/*
+	 * Avoid trapping faults against the zero page. The read-only
+	 * data is likely to be read-cached on the local CPU and
+	 * local/remote hits to the zero page are not interesting.
+	 */
+	if (prot_numa && is_huge_zero_pmd(*pmd))
+		goto unlock;
+
+	if (prot_numa && pmd_protnone(*pmd))
+		goto unlock;
+
+	/*
+	 * In case prot_numa, we are under down_read(mmap_sem). It's critical
+	 * to not clear pmd intermittently to avoid race with MADV_DONTNEED
+	 * which is also under down_read(mmap_sem):
+	 *
+	 *	CPU0:				CPU1:
+	 *				change_huge_pmd(prot_numa=1)
+	 *				 pmdp_huge_get_and_clear_notify()
+	 * madvise_dontneed()
+	 *  zap_pmd_range()
+	 *   pmd_trans_huge(*pmd) == 0 (without ptl)
+	 *   // skip the pmd
+	 *				 set_pmd_at();
+	 *				 // pmd is re-established
+	 *
+	 * The race makes MADV_DONTNEED miss the huge pmd and don't clear it
+	 * which may break userspace.
+	 *
+	 * pmdp_invalidate() is required to make sure we don't miss
+	 * dirty/young flags set by hardware.
+	 */
+	entry = *pmd;
+	pmdp_invalidate(vma, addr, pmd);
+
+	/*
+	 * Recover dirty/young flags.  It relies on pmdp_invalidate to not
+	 * corrupt them.
+	 */
+	if (pmd_dirty(*pmd))
+		entry = pmd_mkdirty(entry);
+	if (pmd_young(*pmd))
+		entry = pmd_mkyoung(entry);
 
+	entry = pmd_modify(entry, newprot);
+	if (preserve_write)
+		entry = pmd_mk_savedwrite(entry);
+	ret = HPAGE_PMD_NR;
+	set_pmd_at(mm, addr, pmd, entry);
+	BUG_ON(vma_is_anonymous(vma) && !preserve_write && pmd_write(entry));
+unlock:
+	spin_unlock(ptl);
 	return ret;
 }
 

mm/z3fold.c

@@ -185,6 +185,12 @@ static inline void z3fold_page_lock(struct z3fold_header *zhdr)
 	spin_lock(&zhdr->page_lock);
 }
 
+/* Try to lock a z3fold page */
+static inline int z3fold_page_trylock(struct z3fold_header *zhdr)
+{
+	return spin_trylock(&zhdr->page_lock);
+}
+
 /* Unlock a z3fold page */
 static inline void z3fold_page_unlock(struct z3fold_header *zhdr)
 {
@@ -385,7 +391,7 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
 			spin_lock(&pool->lock);
 			zhdr = list_first_entry_or_null(&pool->unbuddied[i],
 						struct z3fold_header, buddy);
-			if (!zhdr) {
+			if (!zhdr || !z3fold_page_trylock(zhdr)) {
 				spin_unlock(&pool->lock);
 				continue;
 			}
@@ -394,7 +400,6 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
 			spin_unlock(&pool->lock);
 
 			page = virt_to_page(zhdr);
-			z3fold_page_lock(zhdr);
 			if (zhdr->first_chunks == 0) {
 				if (zhdr->middle_chunks != 0 &&
 				    chunks >= zhdr->start_middle)

mm/zsmalloc.c

@@ -276,7 +276,7 @@ struct zs_pool {
 struct zspage {
 	struct {
 		unsigned int fullness:FULLNESS_BITS;
-		unsigned int class:CLASS_BITS;
+		unsigned int class:CLASS_BITS + 1;
 		unsigned int isolated:ISOLATED_BITS;
 		unsigned int magic:MAGIC_VAL_BITS;
 	};