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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 907F2C43334 for ; Wed, 5 Sep 2018 08:55:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 550C12077C for ; Wed, 5 Sep 2018 08:55:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 550C12077C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz 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 S1728047AbeIENZA (ORCPT ); Wed, 5 Sep 2018 09:25:00 -0400 Received: from mx2.suse.de ([195.135.220.15]:60470 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727201AbeIENZA (ORCPT ); Wed, 5 Sep 2018 09:25:00 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 7A810ADAB; Wed, 5 Sep 2018 08:55:46 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id C792A1E3606; Wed, 5 Sep 2018 10:55:45 +0200 (CEST) Date: Wed, 5 Sep 2018 10:55:45 +0200 From: Jan Kara To: syzbot Cc: ak@linux.intel.com, akpm@linux-foundation.org, jack@suse.cz, jrdr.linux@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mawilcox@microsoft.com, mgorman@techsingularity.net, syzkaller-bugs@googlegroups.com, tim.c.chen@linux.intel.com, zwisler@kernel.org Subject: Re: linux-next test error Message-ID: <20180905085545.GD24902@quack2.suse.cz> References: <0000000000004f6b5805751a8189@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0000000000004f6b5805751a8189@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 05-09-18 00:13:02, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 387ac6229ecf Add linux-next specific files for 20180905 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=149c67a6400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=ad5163873ecfbc32 > dashboard link: https://syzkaller.appspot.com/bug?extid=87a05ae4accd500f5242 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+87a05ae4accd500f5242@syzkaller.appspotmail.com > > INFO: task hung in do_page_mkwriteINFO: task syz-fuzzer:4876 blocked for > more than 140 seconds. > Not tainted 4.19.0-rc2-next-20180905+ #56 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > syz-fuzzer D21704 4876 4871 0x00000000 > Call Trace: > context_switch kernel/sched/core.c:2825 [inline] > __schedule+0x87c/0x1df0 kernel/sched/core.c:3473 > schedule+0xfb/0x450 kernel/sched/core.c:3517 > io_schedule+0x1c/0x70 kernel/sched/core.c:5140 > wait_on_page_bit_common mm/filemap.c:1100 [inline] > __lock_page+0x5b7/0x7a0 mm/filemap.c:1273 > lock_page include/linux/pagemap.h:483 [inline] > do_page_mkwrite+0x429/0x520 mm/memory.c:2391 Waiting for page lock after ->page_mkwrite callback. Which means ->page_mkwrite did not return VM_FAULT_LOCKED but 0. Looking into linux-next... indeed "fs: convert return type int to vm_fault_t" has busted block_page_mkwrite(). It has to return VM_FAULT_LOCKED and not 0 now. Souptick, can I ask you to run 'fstests' for at least common filesystems like ext4, xfs, btrfs when you change generic filesystem code please? That would catch a bug like this immediately. Thanks. Honza -- Jan Kara SUSE Labs, CR