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mm: introduce clear_highpage_kasan_tagged

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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>
This commit is contained in:
Andrey Konovalov 2022-06-09 20:18:46 +02:00 committed by akpm
parent aeaec8e27e
commit d9da8f6cf5
2 changed files with 12 additions and 6 deletions
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10
include/linux/highmem.h
View File

@ -243,6 +243,16 @@ 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)

8
mm/page_alloc.c
View File

@ -1302,12 +1302,8 @@ static void kernel_init_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();
}