From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757405AbdKGPvD (ORCPT ); Tue, 7 Nov 2017 10:51:03 -0500 Received: from mail-io0-f174.google.com ([209.85.223.174]:46758 "EHLO mail-io0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750818AbdKGPvB (ORCPT ); Tue, 7 Nov 2017 10:51:01 -0500 X-Google-Smtp-Source: ABhQp+TxY77SqRAO7L6PUVDywIz7ypp+TktMr2K3p5vog49APOg4+d0GLUQFbpcoGs1fQrIrzzDKGKyNHo0AfxzJEVM= MIME-Version: 1.0 In-Reply-To: <20171107102827.y5pmiqtifzbrlwfo@wfg-t540p.sh.intel.com> References: <20171107100552.jqvf4n7p4ypdeuw7@wfg-t540p.sh.intel.com> <20171107102827.y5pmiqtifzbrlwfo@wfg-t540p.sh.intel.com> From: Linus Torvalds Date: Tue, 7 Nov 2017 07:51:00 -0800 X-Google-Sender-Auth: p6SldlFfxz8fVGrLsENdNSH8SjY Message-ID: Subject: Re: [inotify_read] BUG: unable to handle kernel paging request at ffff8800172f8000 To: Fengguang Wu Cc: linux-fsdevel , Jan Kara , Amir Goldstein , Miklos Szeredi , Nikolay Borisov , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 7, 2017 at 2:28 AM, Fengguang Wu wrote: > FYI This bug trace also contains inotify_read(). > > [ 3.365745] BUG: unable to handle kernel paging request at ffff8800172f8000 > [ 3.366661] IP: slob_free+0x1c4/0x276 > [ 3.373500] RBP: ffff8800172f7ffe Same gcc bug: it's a 2-byte read from the end of the page that has been turned by gcc into a 4-byte read, and causes an oops because your gcc version is bad. I *think* it's triggered by CONFIG_OPTIMIZE_FOR_SIZE=y, which causes gcc to generate garbage code. Yes, the 32-bit read is one byte shorter because it doesn't have a operand size prefix, but it's buggy. Linus