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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>,
	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 1/2] kasan, mm: reset tag when access metadata
Date: Tue, 27 Jul 2021 12:00:20 +0800	[thread overview]
Message-ID: <20210727040021.21371-2-Kuan-Ying.Lee@mediatek.com> (raw)
In-Reply-To: <20210727040021.21371-1-Kuan-Ying.Lee@mediatek.com>

Hardware tag-based KASAN doesn't use compiler instrumentation, we
can not use kasan_disable_current() to ignore tag check.

Thus, we need to reset tags when accessing metadata.

Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
---
 mm/kmemleak.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 228a2fbe0657..73d46d16d575 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -290,7 +290,7 @@ static void hex_dump_object(struct seq_file *seq,
 	warn_or_seq_printf(seq, "  hex dump (first %zu bytes):\n", len);
 	kasan_disable_current();
 	warn_or_seq_hex_dump(seq, DUMP_PREFIX_NONE, HEX_ROW_SIZE,
-			     HEX_GROUP_SIZE, ptr, len, HEX_ASCII);
+			     HEX_GROUP_SIZE, kasan_reset_tag((void *)ptr), len, HEX_ASCII);
 	kasan_enable_current();
 }
 
@@ -1171,7 +1171,7 @@ static bool update_checksum(struct kmemleak_object *object)
 
 	kasan_disable_current();
 	kcsan_disable_current();
-	object->checksum = crc32(0, (void *)object->pointer, object->size);
+	object->checksum = crc32(0, kasan_reset_tag((void *)object->pointer), object->size);
 	kasan_enable_current();
 	kcsan_enable_current();
 
@@ -1246,7 +1246,7 @@ static void scan_block(void *_start, void *_end,
 			break;
 
 		kasan_disable_current();
-		pointer = *ptr;
+		pointer = *(unsigned long *)kasan_reset_tag((void *)ptr);
 		kasan_enable_current();
 
 		untagged_ptr = (unsigned long)kasan_reset_tag((void *)pointer);
-- 
2.18.0


  reply	other threads:[~2021-07-27  4:00 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-27  4:00 [PATCH 0/2] " Kuan-Ying Lee
2021-07-27  4:00 ` Kuan-Ying Lee [this message]
2021-07-27  7:10   ` [PATCH 1/2] " Marco Elver
2021-07-27  8:32     ` Kuan-Ying Lee
2021-07-27  9:34       ` Marco Elver
2021-07-27 19:22       ` Catalin Marinas
2021-07-28 11:05         ` Kuan-Ying Lee
2021-07-28 12:43           ` Marco Elver
2021-07-30 14:57         ` Andrey Konovalov
2021-07-30 15:24           ` Catalin Marinas
2021-07-27  4:00 ` [PATCH 2/2] kasan, mm: reset tag for hex dump address Kuan-Ying Lee
2021-07-27  7:20   ` Marco Elver
2021-07-27  8:54     ` Kuan-Ying Lee

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