merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes

2 files changed, 33 insertions, 5 deletions

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 9cb32e1a78a0..23fc24d16b31 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -309,6 +309,8 @@ static void append_kcore_note(char *notes, size_t *i, const char *name,
 
 static ssize_t read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 {
+	struct file *file = iocb->ki_filp;
+	char *buf = file->private_data;
 	loff_t *fpos = &iocb->ki_pos;
 	size_t phdrs_offset, notes_offset, data_offset;
 	size_t page_offline_frozen = 1;
@@ -555,10 +557,21 @@ static ssize_t read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 		case KCORE_VMEMMAP:
 		case KCORE_TEXT:
 			/*
-			 * We use _copy_to_iter() to bypass usermode hardening
-			 * which would otherwise prevent this operation.
+			 * Sadly we must use a bounce buffer here to be able to
+			 * make use of copy_from_kernel_nofault(), as these
+			 * memory regions might not always be mapped on all
+			 * architectures.
 			 */
-			if (_copy_to_iter((char *)start, tsz, iter) != tsz) {
+			if (copy_from_kernel_nofault(buf, (void *)start, tsz)) {
+				if (iov_iter_zero(tsz, iter) != tsz) {
+					ret = -EFAULT;
+					goto out;
+				}
+			/*
+			 * We know the bounce buffer is safe to copy from, so
+			 * use _copy_to_iter() directly.
+			 */
+			} else if (_copy_to_iter(buf, tsz, iter) != tsz) {
 				ret = -EFAULT;
 				goto out;
 			}
@@ -595,6 +608,10 @@ static int open_kcore(struct inode *inode, struct file *filp)
 	if (ret)
 		return ret;
 
+	filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!filp->private_data)
+		return -ENOMEM;
+
 	if (kcore_need_update)
 		kcore_update_ram();
 	if (i_size_read(inode) != proc_root_kcore->size) {
@@ -605,9 +622,16 @@ static int open_kcore(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+static int release_kcore(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+	return 0;
+}
+
 static const struct proc_ops kcore_proc_ops = {
 	.proc_read_iter	= read_kcore_iter,
 	.proc_open	= open_kcore,
+	.proc_release	= release_kcore,
 	.proc_lseek	= default_llseek,
 };
 
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 74cbb00422ea..15ddf4653a19 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -571,8 +571,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr,
 	bool migration = false;
 
 	if (pmd_present(*pmd)) {
-		/* FOLL_DUMP will return -EFAULT on huge zero page */
-		page = follow_trans_huge_pmd(vma, addr, pmd, FOLL_DUMP);
+		page = vm_normal_page_pmd(vma, addr, *pmd);
 	} else if (unlikely(thp_migration_supported() && is_swap_pmd(*pmd))) {
 		swp_entry_t entry = pmd_to_swp_entry(*pmd);
 
@@ -742,12 +741,14 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 static const struct mm_walk_ops smaps_walk_ops = {
 	.pmd_entry		= smaps_pte_range,
 	.hugetlb_entry		= smaps_hugetlb_range,
+	.walk_lock		= PGWALK_RDLOCK,
 };
 
 static const struct mm_walk_ops smaps_shmem_walk_ops = {
 	.pmd_entry		= smaps_pte_range,
 	.hugetlb_entry		= smaps_hugetlb_range,
 	.pte_hole		= smaps_pte_hole,
+	.walk_lock		= PGWALK_RDLOCK,
 };
 
 /*
@@ -1229,6 +1230,7 @@ static int clear_refs_test_walk(unsigned long start, unsigned long end,
 static const struct mm_walk_ops clear_refs_walk_ops = {
 	.pmd_entry		= clear_refs_pte_range,
 	.test_walk		= clear_refs_test_walk,
+	.walk_lock		= PGWALK_WRLOCK,
 };
 
 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
@@ -1606,6 +1608,7 @@ static const struct mm_walk_ops pagemap_ops = {
 	.pmd_entry	= pagemap_pmd_range,
 	.pte_hole	= pagemap_pte_hole,
 	.hugetlb_entry	= pagemap_hugetlb_range,
+	.walk_lock	= PGWALK_RDLOCK,
 };
 
 /*
@@ -1919,6 +1922,7 @@ static int gather_hugetlb_stats(pte_t *pte, unsigned long hmask,
 static const struct mm_walk_ops show_numa_ops = {
 	.hugetlb_entry = gather_hugetlb_stats,
 	.pmd_entry = gather_pte_stats,
+	.walk_lock = PGWALK_RDLOCK,
 };
 
 /*