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authorAndrey Konovalov <andreyknvl@google.com>2018-12-28 00:30:57 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 12:11:44 -0800
commit2813b9c0296259fb11e75c839bab2d958ba4f96c (patch)
tree4f174c60d6f189977d74053b118f8f820ab689f1 /mm/page_alloc.c
parent41eea9cd239c5b3fff726894f85c97f60e5799a3 (diff)
downloadlinux-2813b9c0296259fb11e75c839bab2d958ba4f96c.tar.bz2
kasan, mm, arm64: tag non slab memory allocated via pagealloc
Tag-based KASAN doesn't check memory accesses through pointers tagged with 0xff. When page_address is used to get pointer to memory that corresponds to some page, the tag of the resulting pointer gets set to 0xff, even though the allocated memory might have been tagged differently. For slab pages it's impossible to recover the correct tag to return from page_address, since the page might contain multiple slab objects tagged with different values, and we can't know in advance which one of them is going to get accessed. For non slab pages however, we can recover the tag in page_address, since the whole page was marked with the same tag. This patch adds tagging to non slab memory allocated with pagealloc. To set the tag of the pointer returned from page_address, the tag gets stored to page->flags when the memory gets allocated. Link: http://lkml.kernel.org/r/d758ddcef46a5abc9970182b9137e2fbee202a2c.1544099024.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e95b5b7c9c3d..d245de2124e3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1183,6 +1183,7 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn,
init_page_count(page);
page_mapcount_reset(page);
page_cpupid_reset_last(page);
+ page_kasan_tag_reset(page);
INIT_LIST_HEAD(&page->lru);
#ifdef WANT_PAGE_VIRTUAL