--- /dev/null
+From d9da8f6cf55eeca642c021912af1890002464c64 Mon Sep 17 00:00:00 2001
+From: Andrey Konovalov <andreyknvl@google.com>
+Date: Thu, 9 Jun 2022 20:18:46 +0200
+Subject: mm: introduce clear_highpage_kasan_tagged
+
+From: Andrey Konovalov <andreyknvl@google.com>
+
+commit d9da8f6cf55eeca642c021912af1890002464c64 upstream.
+
+Add a clear_highpage_kasan_tagged() helper that does clear_highpage() on a
+page potentially tagged by KASAN.
+
+This helper is used by the following patch.
+
+Link: https://lkml.kernel.org/r/4471979b46b2c487787ddcd08b9dc5fedd1b6ffd.1654798516.git.andreyknvl@google.com
+Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
+Cc: Alexander Potapenko <glider@google.com>
+Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
+Cc: Dmitry Vyukov <dvyukov@google.com>
+Cc: Marco Elver <elver@google.com>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Cc: Jiri Slaby <jirislaby@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ include/linux/highmem.h | 10 ++++++++++
+ mm/page_alloc.c | 8 ++------
+ 2 files changed, 12 insertions(+), 6 deletions(-)
+
+--- a/include/linux/highmem.h
++++ b/include/linux/highmem.h
+@@ -218,6 +218,16 @@ static inline void clear_highpage(struct
+ kunmap_local(kaddr);
+ }
+
++static inline void clear_highpage_kasan_tagged(struct page *page)
++{
++ u8 tag;
++
++ tag = page_kasan_tag(page);
++ page_kasan_tag_reset(page);
++ clear_highpage(page);
++ page_kasan_tag_set(page, tag);
++}
++
+ #ifndef __HAVE_ARCH_TAG_CLEAR_HIGHPAGE
+
+ static inline void tag_clear_highpage(struct page *page)
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -1287,12 +1287,8 @@ static void kernel_init_free_pages(struc
+
+ /* s390's use of memset() could override KASAN redzones. */
+ kasan_disable_current();
+- for (i = 0; i < numpages; i++) {
+- u8 tag = page_kasan_tag(page + i);
+- page_kasan_tag_reset(page + i);
+- clear_highpage(page + i);
+- page_kasan_tag_set(page + i, tag);
+- }
++ for (i = 0; i < numpages; i++)
++ clear_highpage_kasan_tagged(page + i);
+ kasan_enable_current();
+ }
+