From 6843e5d12eb44055181d45c4f40e954565d5541a Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Thu, 27 Jan 2022 16:25:46 +1100 Subject: [PATCH] FROMGIT: 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 Acked-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Mark Rutland Cc: Peter Collingbourne Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Stephen Rothwell (cherry picked from commit 198c90d52d550749028048dc6a8315d4ea21237e git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm) Bug: 217222520 Change-Id: I05277a0fdb393bd31c64293ef49b76a09be21364 Signed-off-by: Andrey Konovalov --- mm/page_alloc.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 49d05f54fcb7..510fd0b85682 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1362,11 +1362,16 @@ 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