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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS,URIBL_BLOCKED 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 844DEC43387 for ; Wed, 19 Dec 2018 10:12:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E49721850 for ; Wed, 19 Dec 2018 10:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728991AbeLSKMN (ORCPT ); Wed, 19 Dec 2018 05:12:13 -0500 Received: from www262.sakura.ne.jp ([202.181.97.72]:24024 "EHLO www262.sakura.ne.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728979AbeLSKMG (ORCPT ); Wed, 19 Dec 2018 05:12:06 -0500 Received: from fsav105.sakura.ne.jp (fsav105.sakura.ne.jp [27.133.134.232]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id wBJAC553073637; Wed, 19 Dec 2018 19:12:05 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav105.sakura.ne.jp (F-Secure/fsigk_smtp/530/fsav105.sakura.ne.jp); Wed, 19 Dec 2018 19:12:05 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/530/fsav105.sakura.ne.jp) Received: from [192.168.1.8] (softbank126126163036.bbtec.net [126.126.163.36]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id wBJAC0Z8072069 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NO); Wed, 19 Dec 2018 19:12:05 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Subject: Re: INFO: rcu detected stall in sys_sendfile64 To: syzbot , syzkaller-bugs@googlegroups.com, Ingo Molnar , Peter Zijlstra References: <000000000000e728ec057d5c9d90@google.com> Cc: jmorris@namei.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, serge@hallyn.com From: Tetsuo Handa Message-ID: Date: Wed, 19 Dec 2018 19:11:58 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.3 MIME-Version: 1.0 In-Reply-To: <000000000000e728ec057d5c9d90@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 2018/12/19 18:27, syzbot wrote: > HEAD commit: ddfbab46539f Merge tag 'scsi-fixes' of git://git.kernel.or.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=15b87fa3400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=861a3573f4e78ba1 > dashboard link: https://syzkaller.appspot.com/bug?extid=bcad772bbc241b4c6147 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13912ccd400000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=145781db400000 This is not a LSM problem, for the reproducer is calling sched_setattr(SCHED_DEADLINE) with very large values. sched_setattr(0, {size=0, sched_policy=0x6 /* SCHED_??? */, sched_flags=0, sched_nice=0, sched_priority=0, sched_runtime=2251799813724439, sched_deadline=4611686018427453437, sched_period=0}, 0) = 0 I think that this problem is nothing but an insane sched_setattr() parameter. #syz invalid