From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4A7341FB7 for ; Fri, 25 Mar 2022 01:10:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16E03C340ED; Fri, 25 Mar 2022 01:10:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648170626; bh=V5z8XG7cnJZXzUe4q6SthEHoGkaz3Zlgp/+W+Cq1vUY=; h=Date:To:From:In-Reply-To:Subject:From; b=BZZzy/fq4kzy1gYypPcxSC/R62veOedpMYpX5hYaFVZ8e67BpeuJbo2zSAtDGC9Wv l7PYdPsip6mk4KHxWGbtO4hc8CMo7BWuTGK4mU9LIhw3WdQhjCxo02cbectIapxGYl 5h6Lg0Fl6Bnk37r7CYRFQhGEICEPdMzUxlwjqi9s= Date: Thu, 24 Mar 2022 18:10:25 -0700 To: will@kernel.org,vincenzo.frascino@arm.com,ryabinin.a.a@gmail.com,pcc@google.com,mark.rutland@arm.com,glider@google.com,eugenis@google.com,elver@google.com,dvyukov@google.com,catalin.marinas@arm.com,andreyknvl@google.com,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220324180758.96b1ac7e17675d6bc474485e@linux-foundation.org> Subject: [patch 037/114] kasan: only apply __GFP_ZEROTAGS when memory is zeroed Message-Id: <20220325011026.16E03C340ED@smtp.kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Andrey Konovalov Subject: kasan: only apply __GFP_ZEROTAGS when memory is zeroed __GFP_ZEROTAGS should only be effective if memory is being zeroed. Currently, hardware tag-based KASAN violates this requirement. Fix by including an initialization check along with checking for __GFP_ZEROTAGS. Link: https://lkml.kernel.org/r/f4f4593f7f675262d29d07c1938db5bd0cd5e285.1643047180.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Acked-by: Marco Elver Cc: Andrey Ryabinin Cc: Catalin Marinas Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Mark Rutland Cc: Peter Collingbourne Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/kasan/hw_tags.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/kasan/hw_tags.c~kasan-only-apply-__gfp_zerotags-when-memory-is-zeroed +++ a/mm/kasan/hw_tags.c @@ -199,11 +199,12 @@ void kasan_alloc_pages(struct page *page * page_alloc.c. */ bool init = !want_init_on_free() && want_init_on_alloc(flags); + bool init_tags = init && (flags & __GFP_ZEROTAGS); if (flags & __GFP_SKIP_KASAN_POISON) SetPageSkipKASanPoison(page); - if (flags & __GFP_ZEROTAGS) { + if (init_tags) { int i; for (i = 0; i != 1 << order; ++i) _