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authorWill Deacon <will@kernel.org>2022-07-25 10:57:08 +0100
committerWill Deacon <will@kernel.org>2022-07-25 10:57:08 +0100
commitc436500d9f03ecaf791674046e25ba85a1176454 (patch)
treec93c44d166f232c7316899dbbba39e65f0bc3751 /mm
parent03939cf0d5d5eaf4141c594e427eb5ba14fbcd91 (diff)
parent20794545c14692094a882d2221c251c4573e6adf (diff)
Merge branch 'for-next/mte' into for-next/core
* for-next/mte: arm64: kasan: Revert "arm64: mte: reset the page tag in page->flags" mm: kasan: Skip page unpoisoning only if __GFP_SKIP_KASAN_UNPOISON mm: kasan: Skip unpoisoning of user pages mm: kasan: Ensure the tags are visible before the tag in page->flags
Diffstat (limited to 'mm')
-rw-r--r--mm/kasan/common.c3
-rw-r--r--mm/page_alloc.c19
2 files changed, 12 insertions, 10 deletions
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index c40c0e7b3b5f..78be2beb7453 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -108,9 +108,10 @@ void __kasan_unpoison_pages(struct page *page, unsigned int order, bool init)
return;
tag = kasan_random_tag();
+ kasan_unpoison(set_tag(page_address(page), tag),
+ PAGE_SIZE << order, init);
for (i = 0; i < (1 << order); i++)
page_kasan_tag_set(page + i, tag);
- kasan_unpoison(page_address(page), PAGE_SIZE << order, init);
}
void __kasan_poison_pages(struct page *page, unsigned int order, bool init)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e008a3df0485..bf45a6aa407a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2361,7 +2361,7 @@ static inline bool check_new_pcp(struct page *page, unsigned int order)
}
#endif /* CONFIG_DEBUG_VM */
-static inline bool should_skip_kasan_unpoison(gfp_t flags, bool init_tags)
+static inline bool should_skip_kasan_unpoison(gfp_t flags)
{
/* Don't skip if a software KASAN mode is enabled. */
if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
@@ -2373,12 +2373,10 @@ static inline bool should_skip_kasan_unpoison(gfp_t flags, bool init_tags)
return true;
/*
- * With hardware tag-based KASAN enabled, skip if either:
- *
- * 1. Memory tags have already been cleared via tag_clear_highpage().
- * 2. Skipping has been requested via __GFP_SKIP_KASAN_UNPOISON.
+ * With hardware tag-based KASAN enabled, skip if this has been
+ * requested via __GFP_SKIP_KASAN_UNPOISON.
*/
- return init_tags || (flags & __GFP_SKIP_KASAN_UNPOISON);
+ return flags & __GFP_SKIP_KASAN_UNPOISON;
}
static inline bool should_skip_init(gfp_t flags)
@@ -2397,6 +2395,7 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags) &&
!should_skip_init(gfp_flags);
bool init_tags = init && (gfp_flags & __GFP_ZEROTAGS);
+ int i;
set_page_private(page, 0);
set_page_refcounted(page);
@@ -2422,8 +2421,6 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
* should be initialized as well).
*/
if (init_tags) {
- int i;
-
/* Initialize both memory and tags. */
for (i = 0; i != 1 << order; ++i)
tag_clear_highpage(page + i);
@@ -2431,13 +2428,17 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
/* Note that memory is already initialized by the loop above. */
init = false;
}
- if (!should_skip_kasan_unpoison(gfp_flags, init_tags)) {
+ if (!should_skip_kasan_unpoison(gfp_flags)) {
/* Unpoison shadow memory or set memory tags. */
kasan_unpoison_pages(page, order, init);
/* Note that memory is already initialized by KASAN. */
if (kasan_has_integrated_init())
init = false;
+ } else {
+ /* Ensure page_address() dereferencing does not fault. */
+ for (i = 0; i != 1 << order; ++i)
+ page_kasan_tag_reset(page + i);
}
/* If memory is still not initialized, do it now. */
if (init)