From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: 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@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_poison.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/mm/page_poison.c~kasan-fix-conflict-with-page-poisoning +++ a/mm/page_poison.c @@ -77,12 +77,14 @@ static void unpoison_page(struct page *p 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); } _
