Commit 06b1f855 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Linus Torvalds
Browse files

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: default avatarAndrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent df41872b

mm/page_poison.c

+3 −1
Original line number Diff line number Diff line
@@ -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);

}