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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>,
        Marco Elver <elver@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Chinwen Chang <chinwen.chang@mediatek.com>,
        Nicholas Tang <nicholas.tang@mediatek.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 5.13 151/151] kasan, slub: reset tag when printing address
Date:   Mon, 16 Aug 2021 15:03:01 +0200
Message-Id: <20210816125449.058559553@linuxfoundation.org>
In-Reply-To: <20210816125444.082226187@linuxfoundation.org>
References: <20210816125444.082226187@linuxfoundation.org>
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From: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>

commit 340caf178ddc2efb0294afaf54c715f7928c258e upstream.

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.

Link: https://lkml.kernel.org/r/20210804090957.12393-3-Kuan-Ying.Lee@mediatek.com
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>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Nicholas Tang <nicholas.tang@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 mm/slub.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/slub.c
+++ b/mm/slub.c
@@ -551,8 +551,8 @@ static void print_section(char *level, c
 			  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();
 }