From 9384d79249d04b03572abb7e551a35d99c9268c0 Mon Sep 17 00:00:00 2001 From: "Fabio M. De Francesco" Date: Mon, 6 Jun 2022 16:15:33 +0200 Subject: mm/highmem: delete memmove_page() Matthew Wilcox reported that, while he was looking at memmove_page(), he realized that it can't actually work. The reasons are hidden in its implementation, which makes use of memmove() on logical addresses provided by kmap_local_page(). memmove() does the wrong thing when it tests "if (dest <= src)". Therefore, delete memmove_page(). No need to change any other code because we have no call sites of memmove_page() across the whole kernel. Link: https://lkml.kernel.org/r/20220606141533.555-1-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco Reported-by: Matthew Wilcox Reviewed-by: Baoquan He Reviewed-by: Ira Weiny Cc: Sebastian Andrzej Siewior Signed-off-by: Andrew Morton --- include/linux/highmem.h | 13 ------------- 1 file changed, 13 deletions(-) (limited to 'include/linux/highmem.h') diff --git a/include/linux/highmem.h b/include/linux/highmem.h index 3af34de54330..fee9835e3793 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -336,19 +336,6 @@ static inline void memcpy_page(struct page *dst_page, size_t dst_off, kunmap_local(dst); } -static inline void memmove_page(struct page *dst_page, size_t dst_off, - struct page *src_page, size_t src_off, - size_t len) -{ - char *dst = kmap_local_page(dst_page); - char *src = kmap_local_page(src_page); - - VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE); - memmove(dst + dst_off, src + src_off, len); - kunmap_local(src); - kunmap_local(dst); -} - static inline void memset_page(struct page *page, size_t offset, int val, size_t len) { -- cgit v1.2.3-70-g09d2 From d9da8f6cf55eeca642c021912af1890002464c64 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 9 Jun 2022 20:18:46 +0200 Subject: mm: introduce clear_highpage_kasan_tagged 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 --- include/linux/highmem.h | 10 ++++++++++ mm/page_alloc.c | 8 ++------ 2 files changed, 12 insertions(+), 6 deletions(-) (limited to 'include/linux/highmem.h') diff --git a/include/linux/highmem.h b/include/linux/highmem.h index fee9835e3793..22379a63e293 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -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) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 9234863f2488..248469134962 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_kasan_tagged(page + i); kasan_enable_current(); } -- cgit v1.2.3-70-g09d2