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[13/16] kasan: fix conflict with page poisoning

Message ID 20210409202738.zz1hd8EMu%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [01/16] MAINTAINERS: update CZ.NIC's Turris information | expand

Commit Message

Andrew Morton April 9, 2021, 8:27 p.m. UTC 
From: Andrey Konovalov <andreyknvl@google.com>
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@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>
---

 mm/page_poison.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

--- 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);
 }