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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 <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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2021-04-09 13:27:38 -07:00 committed by Linus Torvalds
parent df41872b68
commit 06b1f85588
1 changed files with 3 additions and 1 deletions
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4
mm/page_poison.c
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@ -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);
}