From 06b1f85588948bd4c772845e5d6891b8f6082248 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 9 Apr 2021 13:27:38 -0700 Subject: [PATCH] kasan: fix conflict with page poisoning When page poisoning is enabled, it accesses memory that is marked as poisoned by KASAN, which leas to false-positive KASAN reports. Suppress the reports by adding KASAN annotations to unpoison_page() (poison_page() already has them). Link: https://lkml.kernel.org/r/2dc799014d31ac13fd97bd906bad33e16376fc67.1617118501.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Cc: Alexander Potapenko Cc: Marco Elver Cc: Dmitry Vyukov Cc: Andrey Ryabinin Cc: Andrey Konovalov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_poison.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/page_poison.c b/mm/page_poison.c index 65cdf844c8ad..655dc5895604 100644 --- a/mm/page_poison.c +++ b/mm/page_poison.c @@ -77,12 +77,14 @@ static void unpoison_page(struct page *page) void *addr; addr = kmap_atomic(page); + kasan_disable_current(); /* * Page poisoning when enabled poisons each and every page * that is freed to buddy. Thus no extra check is done to * see if a page was poisoned. */ - check_poison_mem(addr, PAGE_SIZE); + check_poison_mem(kasan_reset_tag(addr), PAGE_SIZE); + kasan_enable_current(); kunmap_atomic(addr); } -- 2.39.5