From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: raw disks no longer work in latest kvm (kvm-88 was fine) Date: Sun, 07 Mar 2010 19:30:06 +0200 Message-ID: <4B93E29E.6090609@redhat.com> References: <4B92BF97.4040001@nagafix.co.uk> <4B92C90B.4030807@msgid.tls.msk.ru> <4B932829.8090503@nagafix.co.uk> <4B9372B6.3050408@msgid.tls.msk.ru> <20100307100022.GA23201@infradead.org> <4B93A624.8010707@nagafix.co.uk> <4B93AF8A.3070805@nagafix.co.uk> <4B93C2F9.7030904@msgid.tls.msk.ru> <4B93DE3F.4090103@nagafix.co.uk> <4B93DFF0.5050905@redhat.com> <20100307172151.GA24859@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Antoine Martin , Michael Tokarev , kvm@vger.kernel.org To: Christoph Hellwig Return-path: Received: from mx1.redhat.com ([209.132.183.28]:60954 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751584Ab0CGRaU (ORCPT ); Sun, 7 Mar 2010 12:30:20 -0500 In-Reply-To: <20100307172151.GA24859@infradead.org> Sender: kvm-owner@vger.kernel.org List-ID: On 03/07/2010 07:21 PM, Christoph Hellwig wrote: > On Sun, Mar 07, 2010 at 07:18:40PM +0200, Avi Kivity wrote: > >>> The only things that stands out is this before the "read failed" message: >>> [pid 9098] lseek(12, 0, SEEK_END) = 1321851815424 >>> [pid 9121] pread(12, 0x7fa50a0e47d0, 2048, 0) = -1 EINVAL (Invalid >>> argument) >>> >>> >> The buffer is unaligned here, yet the file was opened with O_DIRECT >> (cache=none). This is strange, since alignment is not related to disk >> size. >> > The other interesting thing is that it's using pread - which means > it's a too old kernel to use preadv and thus a not very well tested > codepath with current qemu. > It may also be that glibc is emulating preadv, incorrectly. Antoine, can you check this? ltrace may help, or run 'strings libc.so | grep pread'. -- error compiling committee.c: too many arguments to function