From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:60908 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S375361AbgJWOqp (ORCPT ); Fri, 23 Oct 2020 10:46:45 -0400 Date: Fri, 23 Oct 2020 16:47:18 +0200 From: 'Greg KH' Subject: Re: Buggy commit tracked to: "Re: [PATCH 2/9] iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c" Message-ID: <20201023144718.GA2525489@kroah.com> References: <5fd6003b-55a6-2c3c-9a28-8fd3a575ca78@redhat.com> <20201022104805.GA1503673@kroah.com> <20201022121849.GA1664412@kroah.com> <98d9df88-b7ef-fdfb-7d90-2fa7a9d7bab5@redhat.com> <20201022125759.GA1685526@kroah.com> <20201022135036.GA1787470@kroah.com> <134f162d711d466ebbd88906fae35b33@AcuMS.aculab.com> <935f7168-c2f5-dd14-7124-412b284693a2@redhat.com> <999e2926-9a75-72fd-007a-1de0af341292@redhat.com> <35d0ec90ef4f4a35a75b9df7d791f719@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <35d0ec90ef4f4a35a75b9df7d791f719@AcuMS.aculab.com> List-ID: To: David Laight Cc: 'David Hildenbrand' , Al Viro , Nick Desaulniers , Christoph Hellwig , "kernel-team@android.com" , Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mips@vger.kernel.org" , "linux-parisc@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-s390@vger.kernel.org" , "sparclinux@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-aio@kvack.org" , "io-uring@vger.kernel.org" , "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , "netdev@vger.kernel.org" , "keyrings@vger.kernel.org" , "linux-security-module@vger.kernel.org" On Fri, Oct 23, 2020 at 02:39:24PM +0000, David Laight wrote: > From: David Hildenbrand > > Sent: 23 October 2020 15:33 > ... > > I just checked against upstream code generated by clang 10 and it > > properly discards the upper 32bit via a mov w23 w2. > > > > So at least clang 10 indeed properly assumes we could have garbage and > > masks it off. > > > > Maybe the issue is somewhere else, unrelated to nr_pages ... or clang 11 > > behaves differently. > > We'll need the disassembly from a failing kernel image. > It isn't that big to hand annotate. I've worked around the merge at the moment in the android tree, but it is still quite reproducable, and will try to get a .o file to disassemble on Monday or so... thanks, greg k-h