diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index a939f5e..5c89a07 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -430,6 +430,7 @@
 static ssize_t
 read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
 {
+	char *buf = file->private_data;
 	ssize_t acc = 0;
 	size_t size, tsz;
 	size_t elf_buflen;
@@ -500,23 +501,20 @@
 			if (clear_user(buffer, tsz))
 				return -EFAULT;
 		} else if (is_vmalloc_or_module_addr((void *)start)) {
-			char * elf_buf;
-
-			elf_buf = kzalloc(tsz, GFP_KERNEL);
-			if (!elf_buf)
-				return -ENOMEM;
-			vread(elf_buf, (char *)start, tsz);
+			vread(buf, (char *)start, tsz);
 			/* we have to zero-fill user buffer even if no read */
-			if (copy_to_user(buffer, elf_buf, tsz)) {
-				kfree(elf_buf);
+			if (copy_to_user(buffer, buf, tsz))
 				return -EFAULT;
-			}
-			kfree(elf_buf);
 		} else {
 			if (kern_addr_valid(start)) {
 				unsigned long n;
 
-				n = copy_to_user(buffer, (char *)start, tsz);
+				/*
+				 * Using bounce buffer to bypass the
+				 * hardened user copy kernel text checks.
+				 */
+				memcpy(buf, (char *) start, tsz);
+				n = copy_to_user(buffer, buf, tsz);
 				/*
 				 * We cannot distinguish between fault on source
 				 * and fault on destination. When this happens
@@ -549,6 +547,11 @@
 {
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
+
+	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) {
@@ -559,10 +562,16 @@
 	return 0;
 }
 
+static int release_kcore(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+	return 0;
+}
 
 static const struct file_operations proc_kcore_operations = {
 	.read		= read_kcore,
 	.open		= open_kcore,
+	.release	= release_kcore,
 	.llseek		= default_llseek,
 };
 
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 66a1260..7e3d537 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -571,56 +571,56 @@
  */
 static inline int fault_in_multipages_writeable(char __user *uaddr, int size)
 {
-	int ret = 0;
 	char __user *end = uaddr + size - 1;
 
 	if (unlikely(size == 0))
-		return ret;
+		return 0;
 
+	if (unlikely(uaddr > end))
+		return -EFAULT;
 	/*
 	 * Writing zeroes into userspace here is OK, because we know that if
 	 * the zero gets there, we'll be overwriting it.
 	 */
-	while (uaddr <= end) {
-		ret = __put_user(0, uaddr);
-		if (ret != 0)
-			return ret;
+	do {
+		if (unlikely(__put_user(0, uaddr) != 0))
+			return -EFAULT;
 		uaddr += PAGE_SIZE;
-	}
+	} while (uaddr <= end);
 
 	/* Check whether the range spilled into the next page. */
 	if (((unsigned long)uaddr & PAGE_MASK) ==
 			((unsigned long)end & PAGE_MASK))
-		ret = __put_user(0, end);
+		return __put_user(0, end);
 
-	return ret;
+	return 0;
 }
 
 static inline int fault_in_multipages_readable(const char __user *uaddr,
 					       int size)
 {
 	volatile char c;
-	int ret = 0;
 	const char __user *end = uaddr + size - 1;
 
 	if (unlikely(size == 0))
-		return ret;
+		return 0;
 
-	while (uaddr <= end) {
-		ret = __get_user(c, uaddr);
-		if (ret != 0)
-			return ret;
+	if (unlikely(uaddr > end))
+		return -EFAULT;
+
+	do {
+		if (unlikely(__get_user(c, uaddr) != 0))
+			return -EFAULT;
 		uaddr += PAGE_SIZE;
-	}
+	} while (uaddr <= end);
 
 	/* Check whether the range spilled into the next page. */
 	if (((unsigned long)uaddr & PAGE_MASK) ==
 			((unsigned long)end & PAGE_MASK)) {
-		ret = __get_user(c, end);
-		(void)c;
+		return __get_user(c, end);
 	}
 
-	return ret;
+	return 0;
 }
 
 int add_to_page_cache_locked(struct page *page, struct address_space *mapping,