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Wed, 04 Aug 2021 05:44:33 -0700 (PDT) MIME-Version: 1.0 References: <20210804090957.12393-1-Kuan-Ying.Lee@mediatek.com> <20210804090957.12393-3-Kuan-Ying.Lee@mediatek.com> In-Reply-To: <20210804090957.12393-3-Kuan-Ying.Lee@mediatek.com> From: Andrey Konovalov Date: Wed, 4 Aug 2021 14:44:22 +0200 Message-ID: Subject: Re: [PATCH v3 2/2] kasan, slub: reset tag when printing address To: Kuan-Ying Lee Cc: Nicholas Tang , Andrew Yang , Andrey Ryabinin , Alexander Potapenko , Marco Elver , Catalin Marinas , Chinwen Chang , Andrew Morton , kasan-dev , Linux Memory Management List , LKML , Linux ARM , "moderated list:ARM/Mediatek SoC support" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: C1A1BF00D745 Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=L8CPcLBL; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf11.hostedemail.com: domain of andreyknvl@gmail.com designates 209.85.208.52 as permitted sender) smtp.mailfrom=andreyknvl@gmail.com X-Stat-Signature: 5b9j7fpuzf3ump9rusghttag3fa9rqec X-HE-Tag: 1628081074-857178 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Aug 4, 2021 at 11:10 AM Kuan-Ying Lee wrote: > > 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 > Reviewed-by: Marco Elver > --- > 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 Thanks!