From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Richard W.M. Jones" Subject: Re: kvm [2087]: load/store instruction decoding not implemented Date: Tue, 24 Feb 2015 13:45:33 +0000 Message-ID: <20150224134533.GM11603@redhat.com> References: <20150224115935.GA26241@redhat.com> <20150224122925.GL11603@redhat.com> <20150224124710.GB21364@cbox> <54EC78D1.3030703@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 1417146712 for ; Tue, 24 Feb 2015 08:40:06 -0500 (EST) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id VZbDFgi9eZwE for ; Tue, 24 Feb 2015 08:40:04 -0500 (EST) Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id 275C846710 for ; Tue, 24 Feb 2015 08:40:03 -0500 (EST) Content-Disposition: inline In-Reply-To: <54EC78D1.3030703@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Marc Zyngier Cc: "kvmarm@lists.cs.columbia.edu" List-Id: kvmarm@lists.cs.columbia.edu On Tue, Feb 24, 2015 at 01:12:49PM +0000, Marc Zyngier wrote: > Here's my theory: userspace is accessing something it should never > access (outside of RAM, basically), and doing so via a kernel interface. > > Is this process accessing /dev/mem by any chance? dmidecode anyone? Not as far as I know. The userspace process is inserting modules. Here is the userspace function which is most likely to be running: https://github.com/libguestfs/supermin/blob/master/src/init.c#L292 Unfortunately because of lack of a full stack trace, I can't be sure exactly what system call is failing, but I'll probably add more debug to the userspace program later. BTW this worked fine in 3.19. It's started failing in 3.20/4.0. It also works fine on x86. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/