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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10EFECA9EC6 for ; Wed, 30 Oct 2019 14:38:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CCCCB2087E for ; Wed, 30 Oct 2019 14:38:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CCCCB2087E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7F68D6B028E; Wed, 30 Oct 2019 10:38:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7A6B66B0290; Wed, 30 Oct 2019 10:38:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6E3E86B0291; Wed, 30 Oct 2019 10:38:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0144.hostedemail.com [216.40.44.144]) by kanga.kvack.org (Postfix) with ESMTP id 4B1906B028E for ; Wed, 30 Oct 2019 10:38:18 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id F0491181AEF31 for ; Wed, 30 Oct 2019 14:38:17 +0000 (UTC) X-FDA: 76100706234.25.horn96_2b49772746716 X-HE-Tag: horn96_2b49772746716 X-Filterd-Recvd-Size: 2425 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf09.hostedemail.com (Postfix) with ESMTP for ; Wed, 30 Oct 2019 14:38:17 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 239DE68B05; Wed, 30 Oct 2019 15:38:15 +0100 (CET) Date: Wed, 30 Oct 2019 15:38:14 +0100 From: Christoph Hellwig To: glider@google.com Cc: Andrew Morton , Jens Axboe , Theodore Ts'o , Dmitry Torokhov , "Martin K. Petersen" , "Michael S. Tsirkin" , Christoph Hellwig , Eric Dumazet , Eric Van Hensbergen , Takashi Iwai , Vegard Nossum , Dmitry Vyukov , Matthew Wilcox , linux-mm@kvack.org, viro@zeniv.linux.org.uk, aryabinin@virtuozzo.com, luto@kernel.org, ard.biesheuvel@linaro.org, arnd@arndb.de, gregkh@linuxfoundation.org, harry.wentland@amd.com, herbert@gondor.apana.org.au, mingo@elte.hu, schwidefsky@de.ibm.com, monstr@monstr.eu, pmladek@suse.com, sergey.senozhatsky@gmail.com, rostedt@goodmis.org, tglx@linutronix.de, wsa@the-dreams.de, gor@linux.ibm.com, iii@linux.ibm.com, mark.rutland@arm.com, rdunlap@infradead.org, andreyknvl@google.com, elver@google.com Subject: Re: [PATCH RFC v2 22/25] kmsan: unpoisoning buffers from devices etc. Message-ID: <20191030143814.GC15015@lst.de> References: <20191030142237.249532-1-glider@google.com> <20191030142237.249532-23-glider@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191030142237.249532-23-glider@google.com> User-Agent: Mutt/1.5.17 (2007-11-01) 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, Oct 30, 2019 at 03:22:34PM +0100, glider@google.com wrote: > When data is copied to memory from a device KMSAN should treat it as > initialized. In most cases it's enough to just unpoison the buffer that > is known to come from a device. > In the case with __do_page_cache_readahead() and bio_copy_user_iov() we > have to mark the whole pages as ignored by KMSAN, as it's not obvious > where these pages are read again. A lot of this looks pretty strange. Why don't you instrument the dma_map / dma_sync infrastucture? That should avoid most of the driver hooks.