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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C982C05027 for ; Mon, 23 Jan 2023 20:26:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231893AbjAWU03 (ORCPT ); Mon, 23 Jan 2023 15:26:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56878 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232137AbjAWU01 (ORCPT ); Mon, 23 Jan 2023 15:26:27 -0500 Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72C9E303C5 for ; Mon, 23 Jan 2023 12:26:21 -0800 (PST) Received: from pps.filterd (m0246632.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 30NKE0JK014392; Mon, 23 Jan 2023 20:26:18 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : in-reply-to : references : date : message-id : content-type : content-transfer-encoding : mime-version; s=corp-2022-7-12; bh=mKwDgQcXl4DXFIkkMt6gJP2kJZKthbFmQE+w7MvMEPY=; b=zI/whS6lLqaTXsV0YK/lW/YVI2zIjxASJYQ/yE5d7ZoSQZvVPqh0Ae/a/bo16bGmzNsT nrM9niILqRFliHfjZ/KKavkh4jVn/uc4CV2ZgFaERy2VEqWY/j9Nv7Rn5Bk9Kp3/LPdC Chl6t5csPXQUTaUsl3K+U7twjMu2tekzVJU8w4MF8Q6t+sUZ6mN6IIvG5dX+nVHNmGaD ae7O3vSzaxuG5pHsEpIZXQaMxqrIagJAZwMDrwxidh79hSXnNm2zX/YT7FOqayk9RaQ/ 07ZM279sseuDIU7mBbS8ugVWkUNSJsK2r21kfTjOG5KjbaPEaPUjfJb63CBDl01/MRMM 2Q== Received: from phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (phxpaimrmta01.appoci.oracle.com [138.1.114.2]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 3n87nt3t1j-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 23 Jan 2023 20:26:18 +0000 Received: from pps.filterd (phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com [127.0.0.1]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (8.17.1.5/8.17.1.5) with ESMTP id 30NJ5Tr6011629; Mon, 23 Jan 2023 20:26:17 GMT Received: from nam12-dm6-obe.outbound.protection.outlook.com (mail-dm6nam12lp2171.outbound.protection.outlook.com [104.47.59.171]) by phxpaimrmta01.imrmtpd1.prodappphxaev1.oraclevcn.com (PPS) with ESMTPS id 3n86g3hx1v-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 23 Jan 2023 20:26:17 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Yyo5CxLQhr4/bss+9qsOZrOVOCgM6WSjuUYGZwxG5eyT630k0xSxdujl/Gh30Y5V5kVxlR/oVFUCzlMfIAvdqKMOO6o+gaZHVMpedq9tSqMveAapgYj2wIkIDnYgRntjEdJ3YR/3Nfrs3g0rsFWlU8LOMDj2TG3mHiPuK8LuZZ/c/X4igJfZxT1WdIk0DhtMDDvVric4UVmZru1ZoEvVakwjzimbdqN1Buo3Lgu5Oo/Y6qe8tpoUIP9VnH1hL7sUHYM7NykXWWD+BBGCOB53D4G/FLoi1RcO3zav9GQMj+4YP+nLQQFo8UkSHzKKdcsRNI/inq12f5RCBBzebTt+7Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=mKwDgQcXl4DXFIkkMt6gJP2kJZKthbFmQE+w7MvMEPY=; b=B6e24PhZbYYrn/KppA4vGCzRk4Z0e6BgOiE3YAL3///RagcYMWdciWJL0niKBbc51kqMHC7/jKojM3sENVHQFYgneksDApJMHLY74nGfYGyVghv9nUAA6ivBxa2yKKOtbvx8xHY/tuLE/rRHvfKkJ9ENMZcoSgjgSy+GNwTRVAv4xHz7V9eeti0l+oBrthP4u+wd7jk7gjTnfw4FhtDGtWJBU6NnJDfoPN+JCCGg0BAfNwVBp3fzX6js6Bxfo5nZSNlQenwiKmVd85YE8XHXWuZzIebmHKsukEYX2GzG2BRHp+c5n9kImSxWy6c215H8T3pN1q8kqbLW+STGMy9hLA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=mKwDgQcXl4DXFIkkMt6gJP2kJZKthbFmQE+w7MvMEPY=; b=ezelLYT1LSfNe9RxdcS5CcWHgPzk0yjiJxHVJjPdkF9A5mKetBx7BzAVt3mwHTlB5kWgnKaV0Lh7DRB2rv2SsHAXPXKiD5QZYJPI8O91a+pP0IZe6BQRnL2tAG1rIQKFEcUJ5CVMAzh2r3naecekkQ8DVvk5qT+0+uAoMGAincI= Received: from PH8PR10MB6597.namprd10.prod.outlook.com (2603:10b6:510:226::20) by DM6PR10MB4186.namprd10.prod.outlook.com (2603:10b6:5:218::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.6043.16; Mon, 23 Jan 2023 20:26:15 +0000 Received: from PH8PR10MB6597.namprd10.prod.outlook.com ([fe80::fb4f:8219:b8cc:7084]) by PH8PR10MB6597.namprd10.prod.outlook.com ([fe80::fb4f:8219:b8cc:7084%7]) with mapi id 15.20.6002.024; Mon, 23 Jan 2023 20:26:15 +0000 From: Stephen Brennan To: Petr =?utf-8?B?VGVzYcWZw61r?= Cc: linux-debuggers@vger.kernel.org Subject: Re: Diskdump / kdump format history In-Reply-To: <20230114222936.73730968@meshulam.tesarici.cz> References: <87v8lbcmc9.fsf@oracle.com> <20230114222936.73730968@meshulam.tesarici.cz> Date: Mon, 23 Jan 2023 12:26:13 -0800 Message-ID: <87o7qpngka.fsf@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BY3PR10CA0016.namprd10.prod.outlook.com (2603:10b6:a03:255::21) To PH8PR10MB6597.namprd10.prod.outlook.com (2603:10b6:510:226::20) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH8PR10MB6597:EE_|DM6PR10MB4186:EE_ X-MS-Office365-Filtering-Correlation-Id: 6ceac232-69e8-4e36-ea77-08dafd801347 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH8PR10MB6597.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(39860400002)(366004)(376002)(346002)(396003)(136003)(451199015)(83380400001)(66476007)(66946007)(66556008)(86362001)(6916009)(8676002)(4326008)(66899015)(36756003)(316002)(6506007)(26005)(186003)(6512007)(966005)(6486002)(478600001)(2616005)(8936002)(5660300002)(41300700001)(2906002)(38100700002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UnpDeXJ3U000dEtzUjhFS3JNSGZ2VmpHNTArRloyUXErRDlGRGZzV01XSVc1?= =?utf-8?B?d0VmRGdhbUFvQ1MxeHpRNTBrZTNBdm9vTEVVaGRxemdVam5rSTdST0NWYXMz?= =?utf-8?B?OG4vS2RzNkhMNGZwcU1vTFlRRngzaVdKc2h0dDN1cDNVK2dqOUQvU1BiM3E1?= =?utf-8?B?MFBnMUhmdmwydGkzL25BbDBGL1RxanNnQ0UzQy9vQWZzSzlTQXNpNlVXaVZF?= =?utf-8?B?SUFuNS9ub01aVlNRekp1bGR6OUZRNzhYS2NZajBkdWY3MWdwb2ovajlGbEds?= =?utf-8?B?OG9MRVJUSFdYNXB1QkFlRm9GdTFVUVFKZGhZSGdTa0k3NDJ3V1A4L3A2bzlt?= =?utf-8?B?U0IrVVdUZHFoZTNYaFFaN01rKy8zZVNHSzRvTTRtU1RrVDhoVko3NGhtWlJE?= =?utf-8?B?MUtReklBRU1sZHQwN1BLUlQ0aHNsdHpzQmtadllhUkNRL3REM1NFZWVicDVH?= =?utf-8?B?Rlo3QXVxVVg5Lyt6ZlFvUnozUlRGSjlmbU8vZmNzVnJCdUtBeUJmdUlXVFFv?= =?utf-8?B?RS82Z2FjRUJ0a0RtVU9qZEFacTBva2VYTFNOUE1FYkp6TWhxaWJaSDV6c2F3?= =?utf-8?B?TWRsY3NEWnRtRlQ0eENWWlFPOFJwSVRBdUs0cTVOMVY4MCtJRWNvcUZFS3pY?= =?utf-8?B?U0cwYlkzTXhLQUZDL2RaajE1ajN1a1c4M0NxUmMyV2V5Q0lWazlJQ21iTldj?= =?utf-8?B?QnFFajdkN1dQWXhSMTVieVlVNExvekVUN0pNWkVtWGRnUnNFcXRkZzZoMXZX?= =?utf-8?B?bHFac1VUUjlCRk1pKzRJTjQwL0hFRm5NMnNObWtRakJrQmJGTkUvemJSdHVl?= =?utf-8?B?enNXQ1BXdVFUTmdmd0Vrc0RrNk9NOVJBUjhGa0c5UEFwQVk5ZXd0c0Q2ck1C?= =?utf-8?B?V1Z0bnEvekVUcU1BSVRSQU9SOStaa25WUTY4bUJRQ0NiVCtNTG9KeW9qU1V2?= =?utf-8?B?bjNVT3YzTVJUMXRMVExlV3Fycy9mVDAyN3hEWE5WcnU0MjVaUDRsbDE2cVJh?= =?utf-8?B?aFdDam9SZVhheDhQVTBTdDBVQWxJMzhZaHVDd2FwbkZrSlZvSXNKSGtDSVNF?= =?utf-8?B?Q2dhM1BUNkZoU3UzOHp0WFM1bDZ6TnZoN1J3SmJOKzhHL01JYlI2dEJuZm5t?= =?utf-8?B?WVd1bEVrK2N0aDdDdVU1eHV1OCs1cDYwUXpBcmJPaUVXdURvYW9Ic0FNNkwr?= =?utf-8?B?VG1LejRUOTMxdm1vR0ZRK05uczN3ZzAxTytGM3J4N0ZTZjUwMG5kZlgyVGFv?= =?utf-8?B?dm1TTDFkTjIyZHJwRHRxM0gySE9LWm9RNUd5UEVrTS9RTHNFZ0pBZGVIZEZi?= =?utf-8?B?M1Y3TlFySHFDYnZKSXBIMUsvNC92WWFEZFI4bWNuR0NLVnkvSXlUSXVjTGN1?= =?utf-8?B?SHRZZXVvSWhMSzExdTdLM2hYLys0YWhGbHRvODNMMkY3WThhZmJOOUVsUjR6?= =?utf-8?B?MUQ0UFhoQzZaNk5MVjZIRDNCTTI5MWs5SnRZUEhIUHpCZ1JSV3BLbkpRRHZi?= =?utf-8?B?aVpiY3ZZVWVFTTBQYjBnUjMwVzM4dkJsR2pPb3FSRmFHalJHVG0ydmJCQVh6?= =?utf-8?B?WjEyTkpiSVE0cDl0dG43NGhha1F2Z0FPWk9lYmQ2QnFTclkweFdPVFJWcU56?= =?utf-8?B?QVJVV29VMk5zdUdoOS91OWdZY0l0YisrUTh6ZFBJQVVRWFNmV3RUTzBQL2U4?= =?utf-8?B?Qm9ackR4ZWozNGdTLzlEdE5adk03Q29tSE01SFFmaEJGNE96Q2c5SHJOOVRp?= =?utf-8?B?L0NXZ09rZkU5YTBZclBKOGpVMFh3emtrTkk5QnBLSkZvOW5VUFBGT055aURT?= =?utf-8?B?WTZSUmJPK3NMcm9JOXZNQmNLaHBVSmppQ1RaYWgveEFEc2VJeFJFTU9hclRD?= =?utf-8?B?cTNCK2d0MnU4S0p0Q21xaGRrVmovdmhsY2t5YjdMcW1xblF2SmwrbzBWTHRw?= =?utf-8?B?eWdDa0dTQTl5NWZXN0c1aEFpdERYMXhJSlNoZlBOTlI5OWM1dlVBc21mcDk2?= =?utf-8?B?TmdqVUFad296RGUzZDRqVWRCUWlYUUIrZk1IUkh4MkErOWxFcHduVDZtMzlP?= =?utf-8?B?Mk12MklVWFNMZEVYK1FEbkNETFArbnBCcHdYcTFvUkpJNDNvc0xFNHJiaytu?= =?utf-8?B?eisyVS81eVh1RFNDaVVpK0c0SGhQbEtoM2haZy9mMWFQUE5MclY5RHliQ2Jn?= =?utf-8?B?M2c9PQ==?= X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6ceac232-69e8-4e36-ea77-08dafd801347 X-MS-Exchange-CrossTenant-AuthSource: PH8PR10MB6597.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Jan 2023 20:26:14.9498 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: EwSfI5zlW9eXvrMEUxmdXXu+bKq4ZayPo5hfNIvuQ9o7BQfj4eX8gp6jKrW3CQGVLwbHnolhSFd4MLHHSbuBiU6Cwb1KT4cEa73F51oyD2o= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR10MB4186 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.122.1 definitions=2023-01-23_12,2023-01-23_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 mlxlogscore=999 malwarescore=0 mlxscore=0 bulkscore=0 adultscore=0 phishscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301230195 X-Proofpoint-ORIG-GUID: IZdOU4GcY_84fyP28T5-xUt9G8WQikc8 X-Proofpoint-GUID: IZdOU4GcY_84fyP28T5-xUt9G8WQikc8 Precedence: bulk List-ID: X-Mailing-List: linux-debuggers@vger.kernel.org Hi Petr, Thank you for these insights, especially regarding the flattened format and the lkdump + diskdump origin stories. I don't have any particular follow-up questions, but I do intend to take a deeper look at the different header files used by different projects and try to build some documentation. I hope to make some content in a community wiki or something which could summarize the high level ideas, and provide links to all the different implementations, past and present. I hope to share any and all of that with you and the rest of the mailing list as I have updates. Thanks again, Stephen Petr Tesa=C5=99=C3=ADk writes: > Hi Stephen, > > thanks for your trust. I've been around for some time, but I actually > came late to the party. Below is my understanding of what happened. > People who were really involved in all that may add a lot of > corrections. > > On Thu, 12 Jan 2023 16:25:10 -0800 > Stephen Brennan wrote: > >>[...] >> First, regarding naming. I guess I always assumed that "diskdump" >> referred to some older utility which performed the same function that >> makedumpfile now is commonly used for. Is that the case? > > Not quite. It did not perform the same function... > > Let me make a short historical excursion. > > When I joined SUSE, SLES9 was the latest release and it was based > on kernel 2.6.5. There was no kdump at that time, but a team at > SGI worked on LKCD (Linux Kernel Crash Dumps), which was an > out-of-tree patch to the Linux Kernel, some user-space tools for > setting it up and the lcrash analysis tool (which was, as a matter > of fact, simply horrible). Most importantly, the dumping itself > was performed by the crashed kernel, using a special polling mode > that was implemented by a few device drivers. LKCD offered two > options: netdump and diskdump. This is most likely where the term > "diskdump" was first coined. > >> Do you know the origin of the diskdump format? > > Yes. Fujitsu developed their own Linux kernel dump project called > lkdump. It was conceptually similar to LKCD, as it also ran within > the crashed kernel, but it did not use the LKCD file format. IIUC > they first modified LKCD for their Mission Critical Linux (or > MCLX), but they soon discovered that there were some issues with > the format itself and designed their own format with the signature > "DISKDUMP". > >> Do you know where to find the code for >> this older diskdump tool, if it existed? > > Yes. Have a look here: > > https://sourceforge.net/projects/lkdump/ > >> Second, I have some confusion regarding headers. I've seen headers for >> files with the content "DISKDUMP" and "KDUMP " -- and according to >> src/kdumpfile/diskdump.c, you have too. diskdump_probe() shows that you >> check for these two headers and set a different description depending on >> which is seen. Do you know why or where these two headers are set, and >> which one is chose in which situation? > > "DISKDUMP" is the signature of the original Fujitsu lkdump > files. "KDUMP " is the signature of the makedumpfile modification > (that's the meaning of "_mod" in makedumpfile's diskdump_mod.h > header file name). Yes, there was a header_version field, but that > wasn't deemed sufficient. Since the lkdump project was not known > to be dead for sure when makedumpfile was written, Ken'ichi > Ohmichi (the original author) was afraid that lkdump might make > conflicting extensions to their format and bump this field, > leading to two incompatible file formats with the same signature. > Note that makedumpfile was a project by NEC, not Fujitsu. > >> Third, sometimes I see an additional header with signature >> "makedumpfile", and a few 64-bit integer fields, and then the >> KDUMP/DISKDUMP header occurs at offset 4096/0x1000. I wonder if you're >> familiar with that header, why or why not it occurs? > > This is the flattened format, which is used if makedumpfile writes > to a file descriptor that cannot be seeked, e.g. a pipe. You > should rearrange the file with "makedumpfile -R" (or the > makedumpfile-R.pl script) to convert it to a standard diskdump > file. > >> Finally, and this one is a long shot, do you know any good central >> document describing the diskdump / kdump format? From everything I can >> tell, it seems very much like a "living standard", one which lives in >> code more than documentation. > > This is very much the case. For the "DISKDUMP" format, whatever is > in makedumpfile's diskdump_mod.h is authoritative. The "KDUMP " > format is essentially dead. > > HTH > Petr T > >> But I would be glad to be wrong here, if >> there's a document which describes the format then I'd love to read it, >> and if not, maybe I could be part of creating it to help everyone out. >>=20 >> Thanks, >> Stephen