diff options
| author | Andrey Konovalov <[email protected]> | 2022-03-24 18:10:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2022-03-24 19:06:46 -0700 |
| commit | db8a04774a8195c529f1e87cd1df87f116559b52 (patch) | |
| tree | c986583a6f888707cd5ad488133123b6cfcbeafc | |
| parent | c3525330a04d0a47b4e11f5cf6d44e21a6520885 (diff) | |
kasan, page_alloc: init memory of skipped pages on free
Since commit 7a3b83537188 ("kasan: use separate (un)poison implementation
for integrated init"), when all init, kasan_has_integrated_init(), and
skip_kasan_poison are true, free_pages_prepare() doesn't initialize the
page. This is wrong.
Fix it by remembering whether kasan_poison_pages() performed
initialization, and call kernel_init_free_pages() if it didn't.
Reordering kasan_poison_pages() and kernel_init_free_pages() is OK, since
kernel_init_free_pages() can handle poisoned memory.
Link: https://lkml.kernel.org/r/1d97df75955e52727a3dc1c4e33b3b50506fc3fd.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <[email protected]>
Acked-by: Marco Elver <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Evgenii Stepanov <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Peter Collingbourne <[email protected]>
Cc: Vincenzo Frascino <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | mm/page_alloc.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 4f1257e39760..3da959402db8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1371,11 +1371,16 @@ static __always_inline bool free_pages_prepare(struct page *page, * With hardware tag-based KASAN, memory tags must be set before the * page becomes unavailable via debug_pagealloc or arch_free_page. */ - if (init && !kasan_has_integrated_init()) - kernel_init_free_pages(page, 1 << order); - if (!skip_kasan_poison) + if (!skip_kasan_poison) { kasan_poison_pages(page, order, init); + /* Memory is already initialized if KASAN did it internally. */ + if (kasan_has_integrated_init()) + init = false; + } + if (init) + kernel_init_free_pages(page, 1 << order); + /* * arch_free_page() can make the page's contents inaccessible. s390 * does this. So nothing which can access the page's contents should |