From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932743AbcHCRNU (ORCPT ); Wed, 3 Aug 2016 13:13:20 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:40770 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932475AbcHCRNS (ORCPT ); Wed, 3 Aug 2016 13:13:18 -0400 Subject: Re: "Failed to create /dev/root: -14" after commit e6978e4bf1 ("ARM: save and reset the address limit when entering an exception") To: Russell King - ARM Linux References: <57A15C41.6000804@roeck-us.net> <20160803083822.GI1041@n2100.armlinux.org.uk> Cc: "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Will Deacon From: Guenter Roeck Message-ID: <57A20896.30300@roeck-us.net> Date: Wed, 3 Aug 2016 08:07:02 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <20160803083822.GI1041@n2100.armlinux.org.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/03/2016 01:38 AM, Russell King - ARM Linux wrote: > On Tue, Aug 02, 2016 at 07:51:45PM -0700, Guenter Roeck wrote: >> Hi, >> >> I see the following crash when running a qemu arm 'kzm' runtime test with >> the current mainline. >> ... >> Failed to create /dev/root: -14 >> >> [ followed by panic ] >> >> A complete log file is at [1]. > > I think it's because of those undefined instructions you're hitting > with the hw-breakpoint code... can you try the patch below please? > > arch/arm/kernel/entry-armv.S | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S > index bc5f50799d75..9f157e7c51e7 100644 > --- a/arch/arm/kernel/entry-armv.S > +++ b/arch/arm/kernel/entry-armv.S > @@ -295,6 +295,7 @@ __und_svc_fault: > bl __und_fault > > __und_svc_finish: > + get_thread_info tsk > ldr r5, [sp, #S_PSR] @ Get SVC cpsr > svc_exit r5 @ return from exception > UNWIND(.fnend ) > Yes, that fixes the problem. Assuming you'll create a patch: Tested-by: Guenter Roeck Does that need to be addressed in qemu, or is it a Linux bug ? Thanks, Guenter