From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 58D20CD98CC for ; Fri, 12 Jun 2026 04:45:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=/go128rmErNISgmXs9cmoyd/VORO9f4PkvOsc4cy53U=; b=nnQ2RHSvqVR/dE+funi0W62SJs djDrVq0+cJ+KBXWg0mM6T+iDHI7EpZCSN10mm+8A2G6U1YC1RoqeCMMHwe4I92vcOiMm7GGUD3Vfq LpY7ueFOCJ4emwNJ56mCWAOEaUHWOpSsd8VF9fxb+rg+YtAISKjhQ6Dpw6Fgl1IbeWTay+UEMzR6U IUFZkR5SywO40rVdMSYwbqHf4P7NXgAqC4ppM8VQjb/bVcHK5GG1+DMqeSWkSOzrp1nTnqdgCQ7Ej OvxexIwKPRsnejveAnUUreLtnNIQtHKro4EAD2NW0lsu1S/MHdpL7WEOHOTxptDdDEIvoQ07gBB+S STJ1YSfA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXtlL-0000000AM6B-2cx2; Fri, 12 Jun 2026 04:44:59 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXtlI-0000000AM5s-3yUT for linux-arm-kernel@lists.infradead.org; Fri, 12 Jun 2026 04:44:58 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D3C722E91; Thu, 11 Jun 2026 21:44:48 -0700 (PDT) Received: from cesw-amp-gbt-1s-m12830-01.blr.arm.com (cesw-amp-gbt-1s-m12830-01.blr.arm.com [10.164.195.31]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E073D3FAF5; Thu, 11 Jun 2026 21:44:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1781239493; bh=SQA3Q3+/82oh45oJTME91UR/PdPgdrsuA9Fdpn4kolY=; h=From:To:Cc:Subject:Date:From; b=C5jJ/wIWZzhIUGdGO9T1hGV6rroAbSN3pDV9MfJilf8tLHrAckiL0S/LKO41BXhZH TcYl95kWuiBGL2H9XMsb2TGyjHPdch3DNT1yTG9y+K52Dm55IzVzSy+Ru4qjMsWBbB MevnQMAJu19h7w8r6XSGIR3dzkoJ3W1yPt0WeTnE= From: Dev Jain To: ryabinin.a.a@gmail.com, akpm@linux-foundation.org, corbet@lwn.net Cc: Dev Jain , glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, workflows@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, kaleshsingh@google.com, 21cnbao@gmail.com, david@kernel.org, will@kernel.org, catalin.marinas@arm.com Subject: [RFC PATCH 0/2] kasan: hw_tags: Add option to tag only at allocation time Date: Fri, 12 Jun 2026 04:44:22 +0000 Message-ID: <20260612044425.763060-1-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260611_214457_148578_7201D7F3 X-CRM114-Status: UNSURE ( 7.92 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Introduce a boot option to tag only at allocation time of the objects. This reduces KASAN MTE overhead, the tradeoff being reduced ability of catching bugs. Now, when a memory object will be freed, it will retain the random tag it had at allocation time. This compromises on catching UAF bugs, till the time the object is not reallocated, at which point it will have a new random tag. Hence, not catching "use-after-free-before-reallocation" and not catching "double-free" will be the compromise for reduced KASAN overhead. This is an RFC because we are not clear about the performance benefit. Android folks, please help with testing! --- Applies on Linus master (9716c086c8e8). Dev Jain (2): kasan: hw_tags: Use KASAN_PAGE_REDZONE for vmalloc redzoning kasan: hw_tags: Add boot option to elide free time poisoning Documentation/dev-tools/kasan.rst | 4 +++ mm/kasan/hw_tags.c | 45 +++++++++++++++++++++++++++++-- mm/kasan/kasan.h | 23 +++++++++++++++- 3 files changed, 69 insertions(+), 3 deletions(-) -- 2.43.0