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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 8FA66C5B578 for ; Wed, 3 Jul 2019 03:59:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 64B9520673 for ; Wed, 3 Jul 2019 03:59:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727144AbfGCD7w (ORCPT ); Tue, 2 Jul 2019 23:59:52 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:19096 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727025AbfGCD7v (ORCPT ); Tue, 2 Jul 2019 23:59:51 -0400 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x633utJI105276 for ; Tue, 2 Jul 2019 23:59:50 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2tggqfya5k-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 02 Jul 2019 23:59:49 -0400 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 3 Jul 2019 04:59:48 +0100 Received: from b06avi18626390.portsmouth.uk.ibm.com (9.149.26.192) by e06smtp02.uk.ibm.com (192.168.101.132) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 3 Jul 2019 04:59:44 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x633xWEe38994416 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 3 Jul 2019 03:59:32 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 80270AE055; Wed, 3 Jul 2019 03:59:43 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 46B18AE051; Wed, 3 Jul 2019 03:59:40 +0000 (GMT) Received: from [9.85.75.18] (unknown [9.85.75.18]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 3 Jul 2019 03:59:39 +0000 (GMT) Subject: Re: Reminder: 22 open syzbot bugs in perf subsystem To: Eric Biggers Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Song Liu , Kan Liang , Alexander Shishkin , Jiri Olsa , Namhyung Kim , syzkaller-bugs@googlegroups.com, Oleg Nesterov , Ravi Bangoria References: <20190702054342.GB27702@sol.localdomain> <5a99f556-7449-55da-d901-0249352a5e15@linux.ibm.com> <20190703035550.GA633@sol.localdomain> From: Ravi Bangoria Date: Wed, 3 Jul 2019 09:29:39 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190703035550.GA633@sol.localdomain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19070303-0008-0000-0000-000002F94F15 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19070303-0009-0000-0000-000022669AE3 Message-Id: <4d6ce02e-9325-4247-3d9b-51cdfcfaee07@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-03_02:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907030048 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eric, On 7/3/19 9:25 AM, Eric Biggers wrote: > On Wed, Jul 03, 2019 at 09:09:55AM +0530, Ravi Bangoria wrote: >> >> >> On 7/2/19 11:13 AM, Eric Biggers wrote: >>> -------------------------------------------------------------------------------- >>> Title: possible deadlock in uprobe_clear_state >>> Last occurred: 164 days ago >>> Reported: 201 days ago >>> Branches: Mainline >>> Dashboard link: https://syzkaller.appspot.com/bug?id=a1ce9b3da349209c5085bb8c4fee753d68c3697f >>> Original thread: https://lkml.kernel.org/lkml/00000000000010a9fb057cd14174@google.com/T/#u >>> >>> Unfortunately, this bug does not have a reproducer. >>> >>> No one replied to the original thread for this bug. >>> >>> If you fix this bug, please add the following tag to the commit: >>> Reported-by: syzbot+1068f09c44d151250c33@syzkaller.appspotmail.com >>> >>> If you send any email or patch for this bug, please consider replying to the >>> original thread. For the git send-email command to use, or tips on how to reply >>> if the thread isn't in your mailbox, see the "Reply instructions" at >>> https://lkml.kernel.org/r/00000000000010a9fb057cd14174@google.com >>> >> >> This is false positive: >> https://marc.info/?l=linux-kernel&m=154925313012615&w=2 >> > > What do you mean "false positive"? Your patch says there can be a deadlock. > Also, your patch hasn't been merged yet. So doesn't it still need to be fixed? Please see Oleg's reply to the patch: https://marc.info/?l=linux-kernel&m=154946017315554&w=2 """ But this is false positive, right? if CPU1 calls update_ref_ctr() then either ->mm_users is already zero so binder_alloc_free_page()->mmget_not_zero() will fail, or the caller of update_ref_ctr() has a reference and thus binder_alloc_free_page()->mmput() can't trigger __mmput() ? """