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,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 DED36C433DF for ; Wed, 1 Jul 2020 15:49:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C534720780 for ; Wed, 1 Jul 2020 15:49:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731951AbgGAPtY (ORCPT ); Wed, 1 Jul 2020 11:49:24 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:51026 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727941AbgGAPtX (ORCPT ); Wed, 1 Jul 2020 11:49:23 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 061FX9mZ020284; Wed, 1 Jul 2020 11:48:58 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 320s291fme-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Jul 2020 11:48:58 -0400 Received: from m0098410.ppops.net (m0098410.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 061FXok1025572; Wed, 1 Jul 2020 11:48:57 -0400 Received: from ppma04ams.nl.ibm.com (63.31.33a9.ip4.static.sl-reverse.com [169.51.49.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 320s291fjg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Jul 2020 11:48:56 -0400 Received: from pps.filterd (ppma04ams.nl.ibm.com [127.0.0.1]) by ppma04ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 061Fdjku001997; Wed, 1 Jul 2020 15:48:53 GMT Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by ppma04ams.nl.ibm.com with ESMTP id 31wwr8d3ph-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 01 Jul 2020 15:48:53 +0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 061Fmp1Q63373420 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 1 Jul 2020 15:48:51 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 209E74C058; Wed, 1 Jul 2020 15:48:51 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 717A84C04A; Wed, 1 Jul 2020 15:48:49 +0000 (GMT) Received: from oc7455500831.ibm.com (unknown [9.145.75.158]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 1 Jul 2020 15:48:49 +0000 (GMT) Subject: Re: linux-next: umh: fix processed error when UMH_WAIT_PROC is used seems to break linux bridge on s390x (bisected) To: Luis Chamberlain , Tetsuo Handa Cc: Christoph Hellwig , "Eric W. Biederman" , ast@kernel.org, axboe@kernel.dk, bfields@fieldses.org, bridge@lists.linux-foundation.org, chainsaw@gentoo.org, christian.brauner@ubuntu.com, chuck.lever@oracle.com, davem@davemloft.net, dhowells@redhat.com, gregkh@linuxfoundation.org, jarkko.sakkinen@linux.intel.com, jmorris@namei.org, josh@joshtriplett.org, keescook@chromium.org, keyrings@vger.kernel.org, kuba@kernel.org, lars.ellenberg@linbit.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-security-module@vger.kernel.org, nikolay@cumulusnetworks.com, philipp.reisner@linbit.com, ravenexp@gmail.com, roopa@cumulusnetworks.com, serge@hallyn.com, slyfox@gentoo.org, viro@zeniv.linux.org.uk, yangtiezhu@loongson.cn, netdev@vger.kernel.org, markward@linux.ibm.com, linux-s390 References: <4e27098e-ac8d-98f0-3a9a-ea25242e24ec@de.ibm.com> <4d8fbcea-a892-3453-091f-d57c03f9aa90@de.ibm.com> <1263e370-7cee-24d8-b98c-117bf7c90a83@de.ibm.com> <20200626025410.GJ4332@42.do-not-panic.com> <20200630175704.GO13911@42.do-not-panic.com> <20200701135324.GS4332@42.do-not-panic.com> <8d714a23-bac4-7631-e5fc-f97c20a46083@i-love.sakura.ne.jp> <20200701153859.GT4332@42.do-not-panic.com> From: Christian Borntraeger Autocrypt: addr=borntraeger@de.ibm.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <20200701153859.GT4332@42.do-not-panic.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-07-01_08:2020-07-01,2020-07-01 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 bulkscore=0 lowpriorityscore=0 suspectscore=0 mlxlogscore=999 impostorscore=0 phishscore=0 cotscore=-2147483648 priorityscore=1501 adultscore=0 mlxscore=0 spamscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2007010110 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 01.07.20 17:38, Luis Chamberlain wrote: > On Wed, Jul 01, 2020 at 11:08:57PM +0900, Tetsuo Handa wrote: >> On 2020/07/01 22:53, Luis Chamberlain wrote: >>>> Well, it is not br_stp_call_user() but br_stp_start() which is expecting >>>> to set sub_info->retval for both KWIFEXITED() case and KWIFSIGNALED() case. >>>> That is, sub_info->retval needs to carry raw value (i.e. without "umh: fix >>>> processed error when UMH_WAIT_PROC is used" will be the correct behavior). >>> >>> br_stp_start() doesn't check for the raw value, it just checks for err >>> or !err. So the patch, "umh: fix processed error when UMH_WAIT_PROC is >>> used" propagates the correct error now. >> >> No. If "/sbin/bridge-stp virbr0 start" terminated due to e.g. SIGSEGV >> (for example, by inserting "kill -SEGV $$" into right after "#!/bin/sh" line), >> br_stp_start() needs to select BR_KERNEL_STP path. We can't assume that >> /sbin/bridge-stp is always terminated by exit() syscall (and hence we can't >> ignore KWIFSIGNALED() case in call_usermodehelper_exec_sync()). > > Ah, well that would be a different fix required, becuase again, > br_stp_start() does not untangle the correct error today really. > I also I think it would be odd odd that SIGSEGV or another signal > is what was terminating Christian's bridge stp call, but let's > find out! > > Note we pass 0 to the options to wait so the mistake here could indeed > be that we did not need KWIFSIGNALED(). I was afraid of this prospect... > as it other implications. > > It means we either *open code* all callers, or we handle this in a > unified way on the umh. And if we do handle this in a unified way, it > then begs the question as to *what* do we pass for the signals case and > continued case. Below we just pass the signal, and treat continued as > OK, but treating continued as OK would also be a *new* change as well. > > For instance (this goes just boot tested, but Christian if you can > try this as well that would be appreciated): Does not help, the bridge stays in DOWN state.