[PATCH 1/2] kasan, mm: reset tag when access metadata

[Kuan-Ying Lee]

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@xxxxxxxxxxxx>
---
 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