From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 73284 invoked by alias); 22 Mar 2018 09:11:42 -0000 Mailing-List: contact elfutils-devel-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Post: List-Help: List-Subscribe: Sender: elfutils-devel-owner@sourceware.org Received: (qmail 71950 invoked by uid 89); 22 Mar 2018 09:11:41 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Checked: by ClamAV 0.99.4 on sourceware.org X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.3 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 spammy= X-Spam-Status: No, score=-3.3 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,SPF_HELO_PASS,SPF_PASS autolearn=ham version=3.3.2 X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on sourceware.org X-Spam-Level: X-HELO: EUR01-DB5-obe.outbound.protection.outlook.com Received: from mail-db5eur01on0108.outbound.protection.outlook.com (HELO EUR01-DB5-obe.outbound.protection.outlook.com) (104.47.2.108) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Thu, 22 Mar 2018 09:11:40 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qtcompany.onmicrosoft.com; s=selector1-qt-io; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=OGxa91k6RCfvMiVQIcdIQjP1MrTWum+et2PYhBwqeLo=; b=p7aDz2U34q4Ft6FBTZLROMx3M8f3YD/Cnp3cWwmoiaap5rJfwPOE/EG/QIG/w1ma2cUfZ58Yys2TvB0vddaf8lA1HvAtGVwAm6HQMflGmPXYCbQEfBDAoi8HgHm/Ht06sBif1UIsbKTk53RlIUqc+K4c2j8LVqgX5PhcpqTmk6Y= Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=ulf.hermann@qt.io; Received: from [10.9.78.31] (62.220.2.194) by DB5PR0201MB1831.eurprd02.prod.outlook.com (2603:10a6:0:32::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P256) id 15.20.588.14; Thu, 22 Mar 2018 09:11:36 +0000 Subject: Re: How to associate Elf with Dwfl_Module returned by dwfl_report_module To: elfutils-devel@sourceware.org References: <3517953.ztkfjMdy38@agathebauer> <20180320220549.GD6269@wildebeest.org> <1946852.ajpeOdNFGP@agathebauer> From: Ulf Hermann Message-ID: <5bed10d0-beb2-be95-b22c-3cadba3ad506@qt.io> Date: Thu, 22 Mar 2018 09:11:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <1946852.ajpeOdNFGP@agathebauer> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [62.220.2.194] X-ClientProxiedBy: AM0PR0102CA0027.eurprd01.prod.exchangelabs.com (2603:10a6:208:14::40) To DB5PR0201MB1831.eurprd02.prod.outlook.com (2603:10a6:0:32::13) X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 98729391-11e8-4294-2ba3-08d58fd4e9d7 X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(5600026)(4604075)(4534165)(4627221)(201703031133081)(201702281549075)(2017052603328)(7153060)(7193020);SRVR:DB5PR0201MB1831; X-Microsoft-Exchange-Diagnostics: 1;DB5PR0201MB1831;3:4Qo+uqea5pwNCK7i44f9d9mvKQ1pFELQqgkbiTFHXmVDR1npBi9Q0MLyuECOYGiTJmSdT/3G9ciZfAb9tNLepHz3HWqEaEuuMDwmtGRuE9chaN6UqSjdAzgX0keyl7CkfoFfY6cFKapsxpUB3N0eK5I4JZkDGvk5UvFyBJPxAvPlVD+tlAcejm+nspQCLEv2rZ1a+s9zuylKkAKM+8AdK0n9fHy14aKAPee3KaLtYJapPEgHHjpzQwEVJsKVVGm7;25:SqsmhrnOvFjEuMEgDQ4vNQblydri1tib6A8waplI+06Nlrk99gKZW+aGorE/PjMTEnSqChXfqe9b7BGq8FP0r7tuJ8T2RsTrAVg4k/N4jVe9dfwhiYW2MRExM/WtaWjOJvC2YED9iu2FjQDc3jDJpAX3YryUICd0Z6LcInlvwBcdFcBp0KxVFIVMTE4199qkJcMAz5HqXYe0hipVAYb6TDgwhPHftNfk5LrQ7DHwqsUeyrh/x1Ix4OwXtHX6v5RjETvquKgtIhKE4H0txSGQKxDAPMqY7BiOrhF0n1IWWlVmfk/vq7O5rJMjUYnDTPrw1iq5doC2JXrnbEXEQuiizg==;31:vfDvp3XfqxyXBUup2YZUJ/A6bsMa25NL2T3mWThB0mCCraSWJafgwHlordb+m8C98OkV6H8HdyLpY5wNW9PXjNJkg16MNfI/aD7i4lJZLTpKs0aC+L7yRJnX3Ez/lSGicOtMCU8Hd3hD4KRgGfgGSDaQRmdCJ6pFFY2wC8Hxswvp5J1WFhIGA6FchuEPzs6BfJxgOUehH46BoL559R+BhuD7m8mLDM3V5kg3rh8fvZA= X-MS-TrafficTypeDiagnostic: DB5PR0201MB1831: X-Microsoft-Exchange-Diagnostics: 1;DB5PR0201MB1831;20: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;4:npe2quLwZYFVWGAgmKlh/i1dI//kGUStK9NR1mNfEGJceFwhJhyoTlF11LoT/MYu7RtGzsHd4ZKr+XH2om/nQ8P1vJcjllKmNPJaTN3No9JnUcakPRCYU+NejrcKGrt6745Uhtnl1MDeDBHI7eOjQ3AZnlD0gmP9S2QKuEantLegtF+kBhAs8A0Pxp8HQPIhPlZqxA6FFkv81PWRsKmO6XxXYrLjXpuN4H1xufLMMBowNtI0zGbZ09E0piwwcUpwAoIbuB2QXsg3iHNO4z8TCL7diypeUv1iCI1ialjd+DVzfLY2royYyBu4ohx26gi1 X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:(211171220733660); X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(6040522)(2401047)(8121501046)(5005006)(3002001)(3231221)(944501327)(52105095)(93006095)(93001095)(10201501046)(6041310)(20161123564045)(20161123558120)(20161123560045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123562045)(6072148)(201708071742011);SRVR:DB5PR0201MB1831;BCL:0;PCL:0;RULEID:;SRVR:DB5PR0201MB1831; X-Forefront-PRVS: 0619D53754 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10019020)(6049001)(39380400002)(396003)(366004)(376002)(39850400004)(346002)(189003)(199004)(26005)(105586002)(446003)(3846002)(6116002)(316002)(229853002)(16576012)(36756003)(186003)(16526019)(6486002)(77096007)(50466002)(76176011)(97736004)(65806001)(65956001)(66066001)(230700001)(25786009)(5660300001)(65826007)(33896004)(6246003)(52116002)(8936002)(86362001)(47776003)(81166006)(2486003)(52146003)(23676004)(81156014)(2950100002)(478600001)(68736007)(6666003)(31686004)(8676002)(74482002)(6916009)(305945005)(7736002)(2906002)(386003)(53936002)(106356001)(58126008)(2351001)(31696002)(2361001)(64126003);DIR:OUT;SFP:1102;SCL:1;SRVR:DB5PR0201MB1831;H:[10.9.78.31];FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; Received-SPF: None (protection.outlook.com: qt.io does not designate permitted sender hosts) X-Microsoft-Exchange-Diagnostics: =?utf-8?B?MTtEQjVQUjAyMDFNQjE4MzE7MjM6b0FyZlAyVFdmVjEyanlMaGxBdW1OZStx?= =?utf-8?B?anFoS1NqM3BOQXNsTUk3ZmcwV2JQNlJ2VFhBNGRKcXBCaUplYzZFYzBlQlhh?= =?utf-8?B?ekR2N1Fyc1QyakU4MlZJVGg4UTlaWmFZVWRiOGZENGFDckZKM0FxeXczZ2xD?= =?utf-8?B?eHpzNko4VUFEWEFwTS9XQWtYMlBTWjhpVEF0eDhJdTJBcmtVWE9rZDlDaGdp?= =?utf-8?B?dmg2UCtpU3dicERXYUxHZUNidVRCcXBrVkdKeUxGTHp5L1IvR2FHOURXaG5H?= =?utf-8?B?UHlTQkwxY252dzNGK2dVQ2MzalRZMHQzYlZjZXlIOTNZUklqczNtUTEzUG9n?= =?utf-8?B?Tis1c2k1NUxwR2VtZ1JVbnNvdFoyM01YQ3ZQVDNwWGZFWHdPTVRtZG54ZXZ4?= =?utf-8?B?bHlGVnlhaEwwdHNYd3ZBdjlzdkZsVFZSMVdLVEFGeXcrWGlqbEFkS2gzRU1x?= =?utf-8?B?TTVBTzBRT1M2WGkzd1NXYmtCQm4wY3VpVW5tL3FEbG5mUERjZjFaRVVLaUxS?= =?utf-8?B?WGJmSGhoUTZURTArOVBtVDhLeDhJdjNhS2lkUGxabW42TnJMUEJRTFV4c215?= =?utf-8?B?dWlLYWxKS0NhNU80R1F6Q3N2YTdhcysrRTAzTmNIM0MwS2hJZkkxUGZMMjVu?= =?utf-8?B?blNtaDdMMzE3U1Btak1MTUJhYlczdEowSW5paldrbWZZZjI3MnZLTUJaSnpW?= =?utf-8?B?bms2djF3TUNlaUVkbUNiam9IVy9mNjIwNTIwL0FGNG84ZnMwUHJkTDlQRWtk?= =?utf-8?B?b2VHYlc5bXBad3NEbEVHeHVLRE5XbVhrZE45V0FFOWgzZmU5WW5vT1pXazN4?= =?utf-8?B?WXJ1dVpGaThrV0hnczdTcEdHdWUyUXFDSXl4UzRTVGRwWUNIMzhKNC9mSFRF?= =?utf-8?B?YnlEajJoVTBwYzIrTUZzaFBsZGJ2dFllV1pwWGRqbVhORmcySmNzR1J6TjZD?= =?utf-8?B?a0dJOUVHbWdDbk9BQkVkWFJ6ZCsrNnU5K20vVFVVbFZTNHphT1I4OHVpa2ky?= =?utf-8?B?cHd5M3g3c1NqNlJzRWhQZ0YyTlBtSTA4KzBDc2ZrZzNYcU1rRVdaVGNrcWYz?= =?utf-8?B?U3pvVEdBUStEWDNnd0JjT2lhR3cyY2s4bVNaR0E3S1k1ZzNHT0tWdld5YlJR?= =?utf-8?B?aWg4UG5rYzhyeDY5SngyQ0NKQ1Z1RUJhOW5FNnVaSU9DT0YvUjdkZng3cnhU?= =?utf-8?B?U1V0QmZ6VE5OSkJ4U1lnaFRSNSs0Ni9WM2dGYmsyQ2o2SmxNdVJvR1owQ2xw?= =?utf-8?B?NE9hMkxYaGRiVlR1elZGZm9xdlA3eW9mRktSTFhtVmhLdC8xVURxemlWR1Jx?= =?utf-8?B?TWR0YnBLdzM1M2pvT1F6WGlRVW5lNE1OVXBuUHRaUDlMZDNmYzRONCtOcVdo?= =?utf-8?B?MURMK2UzRXd3OTZxa25CWE9USDI4bE5hMmthR2tCYVZaWDlUSFZ4cDNTTjBP?= =?utf-8?B?bmdNaStVRXJqbWJ5bURMNFJScmpoUXRRenJhS1BGY3B2ZEZmVkZOdGVWRVJH?= =?utf-8?B?ZzJFSUltTnRYOVJ0Si8rZDJHL21jSUdyeWZFWDE3dGp3cnMzNXFsdmJTVFJI?= =?utf-8?B?MENoK2NyTTBVMlJFQlBjR3JubWNqZUQ0N2J5YWZ1ZHQ1TXNQQzhNK1A3b1di?= =?utf-8?B?K2dWejBsWXpvVjh6SXByay90NnVjTGJnM245c2JJSSs4RGZoNVJLSTBBdHFE?= =?utf-8?B?cmVIQWtheG5rY2lTcldjdjE1dmI1bnZ0L1UvUjVWNFl4QzV0RksyazlTdHFI?= =?utf-8?B?MXZLbzZNV0FnS0ZWVnRmM25qTm52N3JiV1N1Rm0vYnAvNkNaSndFWTVTdUJm?= =?utf-8?B?RWhLOGdwbXZsZWpTbGxUTWhXY0JuNGJ3OEVqYXM5L2VjV0I2b3N6WFBrSFo2?= =?utf-8?Q?ooMFF7Jh+iFV+52Qwy1mprTUdZl7ILsrFy?= X-Microsoft-Antispam-Message-Info: YqpyvTOlibm93HWG4SlKiLTJxWyLkrADgTLgTsfcMxmeW8ImXCpuJ+XCkqPbFpT5DfAU8e3iZrQeRHitUvEEf9FOa3d51uifG7KkdVpIzQHldwX1q4Et5GbcsmM42OQrmqqSYVpF8uvu0S+IsRzDxO+9EovQWuDOjdOVqD/wzg2zOAF4zVRMcJtmJsDyP7d3 X-Microsoft-Exchange-Diagnostics: 1;DB5PR0201MB1831;6:PZT6NX1taFpuNEfrvjaw4lbRaEdWF/0lLepGhXTNMfBLUFlFaSz3ApK8IGyfSvZFfzL/8d6Oz/njyNaMkJJKzAzKM4G6qj04SuuxbeXmCsS2P7EdGUPMM+eMP9Sp6Vs545Pyf7vEOAt1lnuy3Acd4bzh/NeZFbVne5HzGrGu6+vkc84oANcHdilRTx4MhMRndwZ8bUM8qcEpzCSPFkgwRQxoZ6EXFSH8maHKLoGVbVDDjf+3t8pfY5K+jNWVYuZivONhmyEbyyRAP2oTGT+HaZdxmLekHbi+/k+ISh2Xm5e1wYHHlcp1rUafWYiiyqTyceoe8lahJ1ZefgTkKx/m3EhfWpYN1E5i43ckptxdQyA=;5:9JxNiJ15YnVozdiRJ58xchIjeA9W2UlzCHwY5rjfIZ5cnf+LeIdnT1So+VgVArn7j+5OEgBmrea4q0LgZnFkEYOazJWzqHRm6ZLqZN45A7CUk572z1e/z82tyHM35zDigL/oGAIlXDLAuBNQssu6NHyKLsqcZvfr2IzAGVs3SFM=;24:dhJMwqoA/gT+LlLL6L85HvO+NVzZwmRJuFdjWo2u+MfXkVEblTgvn1Jn0KHdC7ClEco8Qj28VfprLo7gLXppLioBXdccc2jJnXWfesAfwxY=;7:bK/b7e2TsAGtducfhob7y2dB6CaByYc9M4VSd2naklP7NTN2e/ZYaFXGy7tLmS8Wp48IxiTCG3pEoySSBAq4HG1ZNfNddzFc0EWsSRReYtHSqhwBZYKOk70PxIttr6vMO3wlZUTS4e4GpnIe2zUMk/gm7o9quhGDD5QGBTCpDnsB5jLZM7YflrQ5kauOmzyvTV5Kr6g3+Hf5bjry1K0xiOZt5jQTVFAsbjvslztqrsZAvUJNHnFLCrGyZk9obRUa SpamDiagnosticOutput: 1:99 SpamDiagnosticMetadata: NSPM X-OriginatorOrg: qt.io X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Mar 2018 09:11:36.0574 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 98729391-11e8-4294-2ba3-08d58fd4e9d7 X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 20d0b167-794d-448a-9d01-aaeccc1124ac X-MS-Exchange-Transport-CrossTenantHeadersStamped: DB5PR0201MB1831 X-IsSubscribed: yes X-SW-Source: 2018-q1/txt/msg00098.txt.bz2 Hi Milian, > I am regularly seeing broken backtraces for samples where I have > the gut feeling that missing reported ELFs are to blame. But we report > everything, except for scenarios where the mmap events seemingly overlap. Actually, at least for perfparser that's not quite true. When perfparser encounters an overlap error, it will throw out the entire set of mappings and restart reporting, with the addresses from the current sample (see PerfSymbolTable::reportElf() and PerfSymbolTable::clearCache()). If that still gives you overlapping ranges, it means perf has not sent all the mmap events and therefore we're reporting the wrong ELF for some address in your sample. That wrong ELF may be larger than the one we actually want and therefore it can overlap some other ELF an address in your sample points to. I've seen that happen. Make sure to keep your sample rate low enough to prevent perf from dropping anything. I realize we could optimize the reporting a bit, with the dwfl_report_end callback Mark mentioned, but if you have addresses into two overlapping ELFs in one sample, that's fundamentally impossible to unwind. Ulf