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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 1E939C43387 for ; Fri, 14 Dec 2018 21:59:30 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B04C22080F for ; Fri, 14 Dec 2018 21:59:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B04C22080F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 43Gkwb1kNmzDrF2 for ; Sat, 15 Dec 2018 08:59:27 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: lists.ozlabs.org; spf=none (mailfrom) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.158.5; helo=mx0a-001b2d01.pphosted.com; envelope-from=mwb@linux.vnet.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 43Gksc08ZDzDqdn for ; Sat, 15 Dec 2018 08:56:51 +1100 (AEDT) Received: from pps.filterd (m0098414.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBELsBMC066694 for ; Fri, 14 Dec 2018 16:56:49 -0500 Received: from e31.co.us.ibm.com (e31.co.us.ibm.com [32.97.110.149]) by mx0b-001b2d01.pphosted.com with ESMTP id 2pckg239cw-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 14 Dec 2018 16:56:49 -0500 Received: from localhost by e31.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 21:56:46 -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 wBELujJS23330998 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 14 Dec 2018 21:56:45 GMT Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1DA387805C; Fri, 14 Dec 2018 21:56:45 +0000 (GMT) Received: from b03ledav004.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7FB7C7805E; Fri, 14 Dec 2018 21:56:43 +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 21:56:43 +0000 (GMT) Subject: Re: [PATCH 2/2] of: __of_detach_node() - remove node from phandle cache To: Rob Herring , Frank Rowand References: <1544769771-5468-1-git-send-email-frowand.list@gmail.com> <1544769771-5468-3-git-send-email-frowand.list@gmail.com> 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 15:56:42 -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: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18121421-8235-0000-0000-00000E38DF0C X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010226; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000271; SDB=6.01131826; UDB=6.00588239; IPR=6.00911957; MB=3.00024694; MTD=3.00000008; XFM=3.00000015; UTC=2018-12-14 21:56:47 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18121421-8236-0000-0000-000043B59D96 Message-Id: <68a9e834-b11d-8b9f-1669-466709257f37@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=2 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-1812140186 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, tlfalcon@linux.vnet.ibm.com, "linux-kernel@vger.kernel.org" , minkim@us.ibm.com, Tyrel Datwyler , linuxppc-dev Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 12/14/2018 11:20 AM, Rob Herring wrote: > On Fri, Dec 14, 2018 at 12:43 AM wrote: >> >> From: Frank Rowand >> >> Non-overlay dynamic devicetree node removal may leave the node in >> the phandle cache. Subsequent calls to of_find_node_by_phandle() >> will incorrectly find the stale entry. Remove the node from the >> cache. >> >> Add paranoia checks in of_find_node_by_phandle() as a second level >> of defense (do not return cached node if detached, do not add node >> to cache if detached). >> >> Reported-by: Michael Bringmann >> Signed-off-by: Frank Rowand >> --- >> drivers/of/base.c | 29 ++++++++++++++++++++++++++++- >> drivers/of/dynamic.c | 3 +++ >> drivers/of/of_private.h | 4 ++++ >> 3 files changed, 35 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/of/base.c b/drivers/of/base.c >> index d599367cb92a..34a5125713c8 100644 >> --- a/drivers/of/base.c >> +++ b/drivers/of/base.c >> @@ -162,6 +162,27 @@ int of_free_phandle_cache(void) >> late_initcall_sync(of_free_phandle_cache); >> #endif >> >> +/* >> + * Caller must hold devtree_lock. >> + */ >> +void __of_free_phandle_cache_entry(phandle handle) >> +{ >> + phandle masked_handle; >> + >> + if (!handle) >> + return; >> + >> + masked_handle = handle & phandle_cache_mask; >> + >> + if (phandle_cache) { >> + if (phandle_cache[masked_handle] && >> + handle == phandle_cache[masked_handle]->phandle) { >> + of_node_put(phandle_cache[masked_handle]); >> + phandle_cache[masked_handle] = NULL; >> + } >> + } >> +} >> + >> void of_populate_phandle_cache(void) >> { >> unsigned long flags; >> @@ -1209,11 +1230,17 @@ 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 (np && of_node_check_flag(np, OF_DETACHED)) { >> + of_node_put(np); >> + phandle_cache[masked_handle] = NULL; > > This should never happen, right? Any time we set OF_DETACHED, the > entry should get removed from the cache. I think we want a WARN here > in case we're in an unexpected state. We don't actually remove the pointer from the phandle cache when we set OF_DETACHED in drivers/of/dynamic.c:__of_detach_node. The phandle cache is currently static within drivers/of/base.c. There are a couple of calls to of_populate_phandle_cache / of_free_phandle_cache within drivers/of/overlay.c, but these are not involved in the device tree updates that occur during LPAR migration. A WARN here would only make sense, if we also arrange to clear the handle. > > Rob 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