From 043fcdc2876029c45bf781a3f9ef31fc0b35e881 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 9 Jun 2022 20:18:46 +0200 Subject: [PATCH] mm: introduce clear_highpage_kasan_tagged 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 Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Marco Elver Signed-off-by: Andrew Morton Cc: Jiri Slaby Signed-off-by: Greg Kroah-Hartman --- include/linux/highmem.h | 10 ++++++++++ mm/page_alloc.c | 8 ++------ 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 39bb9b47fa9c..7037c6bed55c 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -218,6 +218,16 @@ static inline void clear_highpage(struct page *page) 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) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 135a081edb82..a8bd356a4d1e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1287,12 +1287,8 @@ static void kernel_init_free_pages(struct page *page, int numpages) /* 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(); }