[PATCH v3 2/2] kasan, slub: reset tag when printing address - Kuan-Ying Lee

From: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
To: Nicholas Tang <nicholas.tang@mediatek.com>,
	Andrew Yang <andrew.yang@mediatek.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Alexander Potapenko <glider@google.com>,
	Marco Elver <elver@google.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Chinwen Chang <chinwen.chang@mediatek.com>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: <kasan-dev@googlegroups.com>, <linux-mm@kvack.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>,
	Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Subject: [PATCH v3 2/2] kasan, slub: reset tag when printing address
Date: Wed, 4 Aug 2021 17:09:57 +0800	[thread overview]
Message-ID: <20210804090957.12393-3-Kuan-Ying.Lee@mediatek.com> (raw)
In-Reply-To: <20210804090957.12393-1-Kuan-Ying.Lee@mediatek.com>

The address still includes the tags when it is printed.
With hardware tag-based kasan enabled, we will get a
false positive KASAN issue when we access metadata.

Reset the tag before we access the metadata.

Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing metadata")
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Reviewed-by: Marco Elver <elver@google.com>
---
 mm/slub.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index b6c5205252eb..f77d8cd79ef7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -576,8 +576,8 @@ static void print_section(char *level, char *text, u8 *addr,
 			  unsigned int length)
 {
 	metadata_access_enable();
-	print_hex_dump(level, kasan_reset_tag(text), DUMP_PREFIX_ADDRESS,
-			16, 1, addr, length, 1);
+	print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
+			16, 1, kasan_reset_tag((void *)addr), length, 1);
 	metadata_access_disable();
 }
 
-- 
2.18.0

