2022-06-01 19:37:30

by andrey.konovalov

Subject: [PATCH 1/3] mm: rename kernel_init_free_pages to kernel_init_pages

From: Andrey Konovalov <[email protected]>

Rename kernel_init_free_pages() to kernel_init_pages(). This function is
not only used for free pages but also for pages that were just allocated.

Signed-off-by: Andrey Konovalov <[email protected]>
---
mm/page_alloc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e008a3df0485..66ef8c310dce 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1296,7 +1296,7 @@ static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags)
PageSkipKASanPoison(page);
}

-static void kernel_init_free_pages(struct page *page, int numpages)
+static void kernel_init_pages(struct page *page, int numpages)
{
int i;

@@ -1396,7 +1396,7 @@ static __always_inline bool free_pages_prepare(struct page *page,
init = false;
}
if (init)
- kernel_init_free_pages(page, 1 << order);
+ kernel_init_pages(page, 1 << order);

/*
* arch_free_page() can make the page's contents inaccessible. s390
@@ -2441,7 +2441,7 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
}
/* If memory is still not initialized, do it now. */
if (init)
- kernel_init_free_pages(page, 1 << order);
+ kernel_init_pages(page, 1 << order);
/* Propagate __GFP_SKIP_KASAN_POISON to page flags. */
if (kasan_hw_tags_enabled() && (gfp_flags & __GFP_SKIP_KASAN_POISON))
SetPageSkipKASanPoison(page);
--
2.25.1

2022-06-01 20:12:11

by andrey.konovalov

Subject: [PATCH 2/3] mm: introduce clear_highpage_tagged

From: Andrey Konovalov <[email protected]>

Add a clear_highpage_tagged() helper that does clear_highpage() on a
page potentially tagged by KASAN.

This helper is used by the following patch.

Signed-off-by: Andrey Konovalov <[email protected]>
---
include/linux/highmem.h | 11 +++++++++++
mm/page_alloc.c | 8 ++------
2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 3af34de54330..df76a0db7cec 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -243,6 +243,17 @@ static inline void clear_highpage(struct page *page)
kunmap_local(kaddr);
}

+static inline void clear_highpage_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 66ef8c310dce..d82ea983a7a3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -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_tagged(page + i);
kasan_enable_current();
}

--
2.25.1