Thread (5 messages) flat view 5 messages, 2 authors, 2021-08-04

Re: [PATCH v3 2/2] kasan, slub: reset tag when printing address

From: Andrey Konovalov <andreyknvl@gmail.com>
Date: 2021-08-04 12:46:00
Also in: linux-arm-kernel, linux-mm, lkml

On Wed, Aug 4, 2021 at 11:10 AM Kuan-Ying Lee
[off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted>
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
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>

Thanks!

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