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Wed, 04 Aug 2021 01:41:36 -0700 (PDT) MIME-Version: 1.0 References: <20210804082230.10837-1-Kuan-Ying.Lee@mediatek.com> <20210804082230.10837-3-Kuan-Ying.Lee@mediatek.com> In-Reply-To: <20210804082230.10837-3-Kuan-Ying.Lee@mediatek.com> From: Marco Elver Date: Wed, 4 Aug 2021 10:41:25 +0200 Message-ID: Subject: Re: [PATCH v2 2/2] kasan, slub: reset tag when printing address To: Kuan-Ying Lee Cc: Nicholas Tang , Andrew Yang , Andrey Konovalov , Andrey Ryabinin , Alexander Potapenko , Catalin Marinas , Chinwen Chang , Andrew Morton , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: BF0B5F00A290 Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=CdeSijkP; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf11.hostedemail.com: domain of elver@google.com designates 209.85.210.50 as permitted sender) smtp.mailfrom=elver@google.com X-Stat-Signature: 1rw91x9ta78w7y38mruap1n5jpyftday X-HE-Tag: 1628066497-126674 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, 4 Aug 2021 at 10:23, 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 > Suggested-by: Marco Elver Note, in this case Suggested-by is inappropriate, because I did not suggest the change in any way (you already had it in v1). I just commented on the fact that it's missing a Fixes so stable can pick it up and some clarification. 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