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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 01CF2C43387 for ; Fri, 14 Dec 2018 21:58:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2E8CC2080F for ; Fri, 14 Dec 2018 21:58:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731428AbeLNV65 (ORCPT ); Fri, 14 Dec 2018 16:58:57 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:50698 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730987AbeLNV64 (ORCPT ); Fri, 14 Dec 2018 16:58:56 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBELwlK9033817 for ; Fri, 14 Dec 2018 16:58:55 -0500 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0a-001b2d01.pphosted.com with ESMTP id 2pcm2ft28d-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 14 Dec 2018 16:58:55 -0500 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 14 Dec 2018 21:58:52 -0000 Received: from b03ledav004.gho.boulder.ibm.com (b03ledav004.gho.boulder.ibm.com [9.17.130.235]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wBELwpHx20709458 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 14 Dec 2018 21:58:52 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DFB1D78060; Fri, 14 Dec 2018 21:58:51 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4F1B17805E; Fri, 14 Dec 2018 21:58:50 +0000 (GMT) Received: from oc5000245537.ibm.com (unknown [9.80.196.120]) by b03ledav004.gho.boulder.ibm.com (Postfix) with ESMTP; Fri, 14 Dec 2018 21:58:50 +0000 (GMT) Subject: Re: [PATCH v03] powerpc/mobility: Fix node detach/rename problem To: Michael Ellerman , Frank Rowand , Rob Herring Cc: devicetree@vger.kernel.org, tlfalcon@linux.vnet.ibm.com, "linux-kernel@vger.kernel.org" , minkim@us.ibm.com, Tyrel Datwyler , linuxppc-dev References: <871s6oxkdf.fsf@concordia.ellerman.id.au> <48aa028d-b786-7704-70ff-75a6d2321474@gmail.com> <877egew2ur.fsf@concordia.ellerman.id.au> From: Michael Bringmann Openpgp: preference=signencrypt Autocrypt: addr=mwb@linux.vnet.ibm.com; prefer-encrypt=mutual; keydata= xsBNBFcY7GcBCADzw3en+yzo9ASFGCfldVkIg95SAMPK0myXp2XJYET3zT45uBsX/uj9/2nA lBmXXeOSXnPfJ9V3vtiwcfATnWIsVt3tL6n1kqikzH9nXNxZT7MU/7gqzWZngMAWh/GJ9qyg DTOZdjsvdUNUWxtiLvBo7y+reA4HjlQhwhYxxvCpXBeRoF0qDWfQ8DkneemqINzDZPwSQ7zY t4F5iyN1I9GC5RNK8Y6jiKmm6bDkrrbtXPOtzXKs0J0FqWEIab/u3BDrRP3STDVPdXqViHua AjEzthQbGZm0VCxI4a7XjMi99g614/qDcXZCs00GLZ/VYIE8hB9C5Q+l66S60PLjRrxnABEB AAHNLU1pY2hhZWwgVy4gQnJpbmdtYW5uIDxtd2JAbGludXgudm5ldC5pYm0uY29tPsLAeAQT AQIAIgUCVxjsZwIbAwYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQSEdag3dpuTI0NAf8 CKYTDKQLgOSjVrU2L5rM4lXaJRmQV6oidD3vIhKSnWRvPq9C29ifRG6ri20prTHAlc0vycgm 41HHg0y2vsGgNXGTWC2ObemoZBI7mySXe/7Tq5mD/semGzOp0YWZ7teqrkiSR8Bw0p+LdE7K QmT7tpjjvuhrtQ3RRojUYcuy1nWUsc4D+2cxsnZslsx84FUKxPbLagDgZmgBhUw/sUi40s6S AkdViVCVS0WANddLIpG0cfdsV0kCae/XdjK3mRK6drFKv1z+QFjvOhc8QIkkxFD0da9w3tJj oqnqHFV5gLcHO6/wizPx/NV90y6RngeBORkQiRFWxTXS4Oj9GVI/Us7ATQRXGOxnAQgAmJ5Y ikTWrMWPfiveUacETyEhWVl7u8UhZcx3yy2te8O0ay7t9fYcZgIEfQPPVVus89acIXlG3wYL DDPvb21OprLxi+ZJ2a0S5we+LcSWN1jByxJlbWBq+/LcMtGAOhNLpysY1gD0Y4UW/eKS+TFZ 562qKC3k1dBvnV9JXCgeS1taYFxRdVAn+2DwK3nuyG/DDq/XgJ5BtmyC3MMx8CiW3POj+O+l 6SedIeAfZlZ7/xhijx82g93h07VavUQRwMZgZFsqmuxBxVGiav2HB+dNvs3PFB087Pvc9OHe qhajPWOP/gNLMmvBvknn1NToM9a8/E8rzcIZXoYs4RggRRYh6wARAQABwsBfBBgBAgAJBQJX GOxnAhsMAAoJEEhHWoN3abky+RUH/jE08/r5QzaNKYeVhu0uVbgXu5fsxqr2cAxhf+KuwT3T efhEP2alarxzUZdEh4MsG6c+X2NYLbD3cryiXxVx/7kSAJEFQJfA5P06g8NLR25Qpq9BLsN7 ++dxQ+CLKzSEb1X24hYAJZpOhS8ev3ii+M/XIo+olDBKuTaTgB6elrg3CaxUsVgLBJ+jbRkW yQe2S5f/Ja1ThDpSSLLWLiLK/z7+gaqwhnwjQ8Z8Y9D2itJQcj4itHilwImsqwLG7SxzC0NX IQ5KaAFYdRcOgwR8VhhkOIVd70ObSZU+E4pTET1WDz4o65xZ89yfose1No0+r5ht/xWOOrh8 53/hcWvxHVs= Organization: IBM Linux Technology Center Date: Fri, 14 Dec 2018 15:58:49 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <877egew2ur.fsf@concordia.ellerman.id.au> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18121421-0020-0000-0000-00000E99FBAA X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010226; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000271; SDB=6.01131827; UDB=6.00588240; IPR=6.00911958; MB=3.00024694; MTD=3.00000008; XFM=3.00000015; UTC=2018-12-14 21:58:54 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18121421-0021-0000-0000-0000640E9D8E Message-Id: <90fba2b5-139d-ec05-5708-0f0b656b142a@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-12-14_13:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 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-1812140187 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/12/2018 08:57 PM, Michael Ellerman wrote: > Frank Rowand writes: >> On 12/11/18 8:07 AM, Rob Herring wrote: >>> On Tue, Dec 11, 2018 at 7:29 AM Michael Ellerman wrote: > ... >>>> diff --git a/drivers/of/base.c b/drivers/of/base.c >>>> index 09692c9b32a7..d8e4534c0686 100644 >>>> --- a/drivers/of/base.c >>>> +++ b/drivers/of/base.c >>>> @@ -1190,6 +1190,10 @@ struct device_node *of_find_node_by_phandle(phandle handle) >>>> if (phandle_cache[masked_handle] && >>>> handle == phandle_cache[masked_handle]->phandle) >>>> np = phandle_cache[masked_handle]; >>>> + >>>> + /* If we find a detached node, remove it */ >>>> + if (of_node_check_flag(np, OF_DETACHED)) >>>> + np = phandle_cache[masked_handle] = NULL; >> >> The bug you found exposes a couple of different issues, a little bit >> deeper than the proposed fix. I'll work on a fuller fix tonight or >> tomorrow. > > OK thanks. > >>> I'm wondering if we should explicitly remove the node from the cache >>> when we set OF_DETACHED. Otherwise, it could be possible that the node >>> pointer has been freed already. Or maybe we need both? >> >> Yes, it should be explicitly removed. I may also add in a paranoia check in >> of_find_node_by_phandle(). > > That seems best to me. I agree that we should do both. > > cheers Michael -- Michael W. Bringmann Linux I/O, Networking and Security Development IBM Corporation Tie-Line 363-5196 External: (512) 286-5196 Cell: (512) 466-0650 mwb@linux.vnet.ibm.com