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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 53126C32789 for ; Fri, 2 Nov 2018 19:04:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 02F9B2081F for ; Fri, 2 Nov 2018 19:04:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02F9B2081F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ZenIV.linux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726541AbeKCEMz (ORCPT ); Sat, 3 Nov 2018 00:12:55 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:42802 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725728AbeKCEMy (ORCPT ); Sat, 3 Nov 2018 00:12:54 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gIekD-0000UD-P1; Fri, 02 Nov 2018 19:04:33 +0000 Date: Fri, 2 Nov 2018 19:04:33 +0000 From: Al Viro To: Marc Zyngier Cc: David Howells , linux-kernel@vger.kernel.org, Will Deacon Subject: Re: [PATCH] iov_iter: Fix 9p virtio breakage Message-ID: <20181102190433.GZ32577@ZenIV.linux.org.uk> References: <20181102171651.97671-1-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181102171651.97671-1-marc.zyngier@arm.com> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 02, 2018 at 05:16:51PM +0000, Marc Zyngier wrote: > When switching to the new iovec accessors, a negation got subtly > dropped, leading to 9p being remarkably broken (here with kvmtool): > > [ 7.430941] VFS: Mounted root (9p filesystem) on device 0:15. > [ 7.432080] devtmpfs: mounted > [ 7.432717] Freeing unused kernel memory: 1344K > [ 7.433658] Run /virt/init as init process > Warning: unable to translate guest address 0x7e00902ff000 to host > Warning: unable to translate guest address 0x7e00902fefc0 to host > Warning: unable to translate guest address 0x7e00902ff000 to host > Warning: unable to translate guest address 0x7e008febef80 to host > Warning: unable to translate guest address 0x7e008febf000 to host > Warning: unable to translate guest address 0x7e008febef00 to host > Warning: unable to translate guest address 0x7e008febf000 to host > [ 7.436376] Kernel panic - not syncing: Requested init /virt/init failed (error -8). > [ 7.437554] CPU: 29 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc8-02267-g00e23707442a #291 > [ 7.439006] Hardware name: linux,dummy-virt (DT) > [ 7.439902] Call trace: > [ 7.440387] dump_backtrace+0x0/0x148 > [ 7.441104] show_stack+0x14/0x20 > [ 7.441768] dump_stack+0x90/0xb4 > [ 7.442425] panic+0x120/0x27c > [ 7.443036] kernel_init+0xa4/0x100 > [ 7.443725] ret_from_fork+0x10/0x18 > [ 7.444444] SMP: stopping secondary CPUs > [ 7.445391] Kernel Offset: disabled > [ 7.446169] CPU features: 0x0,23000438 > [ 7.446974] Memory Limit: none > [ 7.447645] ---[ end Kernel panic - not syncing: Requested init /virt/init failed (error -8). ]--- > > Restoring the missing "!" brings the guest back to life. > > Fixes: 00e23707442a ("iov_iter: Use accessor function") > Reported-by: Will Deacon > Signed-off-by: Marc Zyngier ACK. Do you want me to take it via vfs.git? Or might as well send directly to Linus, with Acked-by Al Viro on it.