From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932855AbcAZCrp (ORCPT ); Mon, 25 Jan 2016 21:47:45 -0500 Received: from mail-db3on0056.outbound.protection.outlook.com ([157.55.234.56]:50291 "EHLO emea01-db3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932781AbcAZCrh (ORCPT ); Mon, 25 Jan 2016 21:47:37 -0500 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=cmetcalf@ezchip.com; Subject: Re: [PATCH] Add hard/soft lockup debugger entry points To: Jeff Merkey , References: <20160126023607.GA5405@localhost.localdomain> CC: Andrew Morton , Don Zickus , Ulrich Obergfell , Aaron Tomlin , Michal Hocko , Frederic Weisbecker , Tejun Heo , Hidehiro Kawai From: Chris Metcalf Message-ID: <56A6DE4A.3060608@ezchip.com> Date: Mon, 25 Jan 2016 21:47:38 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <20160126023607.GA5405@localhost.localdomain> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [173.76.23.146] X-ClientProxiedBy: BN3PR0401CA0012.namprd04.prod.outlook.com (25.162.159.150) To AMSPR02MB119.eurprd02.prod.outlook.com (10.242.92.150) X-Microsoft-Exchange-Diagnostics: 1;AMSPR02MB119;2:tKhvBc5lFIQVXIWTVHnnKq2D6PGaeItWjVO0JZWqDrQ5VWD3jS77PiDv11GnApd2XO67FEZsazdPKexlgtgxS05dEU7ugcgv+4Z/1HFcn10Wyuu5CROBmtkFlW+lRJwxjFKMNLkP5uDkWKl0l6mbiQ==;3:4CPMPaUhLhgppdk9eukl+qDkitUr6aR2oWjgVZP/w7iT85QokAsYWf1kg/z3BL9IwqHw9iaLtU3c3Vmdu+pB5j5WCqg/tEug5f2BWXtWSbhMqUELT8l5KGWSYs5m/AwG;25:vq7QfTvXr2aJKggMpwUXY+ABoTbOZ0ZRd2fmxllVgdWsdn1NPJCiNKcNTtfyWrJyzfgwwHyxbXSWuTu34nZvys7F0y4aP7f0rkMLdEE/E/Ko6+DsA6Hczur3tqZGBJ9GYKNoasNzB3k6SxnU+xmeh/Sp8N9+6+rTOX2+dvNTERW8Z8sWtRsT/soPo4EdhfoPiZZONMgDHIt02yCTtvDHBlWIoOz7Ik7dde0J6UOa7pyvjK6S0SR6HCQU6VODJXcB;20:mnlp/MqAIdD5iGM4PXOjRDk889hCTjAtcplYDM5wLkxk53XAI8y7Pl6cl41GbEiUlhl74t/ftykB//HamhCm/lWs16rNT+1PCJwYw+HJTm6MF5WeX5Oda4dH7hRsDgT+i6CZznBWlVkd5ZdAQ3eXNX2MYXzgEZzCxE5aQ4rhzi8= X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:AMSPR02MB119; X-MS-Office365-Filtering-Correlation-Id: b824f7a8-b5df-4256-1cc3-08d325fb0b1e X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:(121898900299872); X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(2401047)(8121501046)(520078)(5005006)(3002001)(10201501046);SRVR:AMSPR02MB119;BCL:0;PCL:0;RULEID:;SRVR:AMSPR02MB119; X-Microsoft-Exchange-Diagnostics: 1;AMSPR02MB119;4:cdDS1zYHP20y5DnPSA9acCxVzaiavGQVCAEq836rHweGF/XDJOfLqYPyfT/IXhN5uhElF3WFvOUf2z77f3gzqGbYgeoMP+vixhOGagvQiNE6h7brupFy70quQ8Svq4HpyG6HaBK3glR3JQTgthy7rw+BYaUMOK3xlwRQVcoK4NqW47+dzt8XSgIhnVRvuXOfuorxjYj8q/u+2Zbh8vh0Qf4jIIOc9Nm2kOtPxi98yRDaZ5b3MUdkdHGDuUMuKdlfBZQKdSUjM+gEisDsY5nYyaCvROtYE7AH3YXMBkP2gpW7uOj9zx0kKYIOXLH2zYLfExEOT6gJ3zAjXsP2CEfGqKQIiEFAB/DywMEGEFqeguFCL7m5mSlhRbz9Win5WoYSnSJtNJwCyGOHNmfbLOJmq8SlzLQxNsphCwuy+3z6MrAQ+qkfN5YzS7nlfnbOZOPA X-Forefront-PRVS: 08331F819E X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10009020)(6049001)(6009001)(377454003)(189002)(24454002)(199003)(479174004)(4326007)(80316001)(122386002)(19580405001)(50466002)(2906002)(83506001)(92566002)(40100003)(23746002)(86362001)(59896002)(87976001)(5004730100002)(42186005)(117156001)(64126003)(1096002)(77096005)(36756003)(5001960100002)(15975445007)(230700001)(87266999)(54356999)(3846002)(2950100001)(33656002)(97736004)(81156007)(5001770100001)(6116002)(19580395003)(4001350100001)(65806001)(189998001)(65956001)(101416001)(47776003)(66066001)(5008740100001)(50986999)(106356001)(105586002)(65816999)(586003)(76176999)(2101003)(18886065003);DIR:OUT;SFP:1101;SCL:1;SRVR:AMSPR02MB119;H:[192.168.1.168];FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; X-Microsoft-Exchange-Diagnostics: =?Windows-1252?Q?1;AMSPR02MB119;23:gXGnXpTuqrb8BHxHVD3NQ1j/QG0A48KADBPUXm?= =?Windows-1252?Q?tRVINap5jgeyM/4KLmEvLi8bjI3FvcS5NCT7csSqvD1WZ9XWwQnfkyQP?= =?Windows-1252?Q?snChdoSIi6BG9czgBBxpP4ZRGOt/kraX5fLJ7k7W6xBaSlbluDXEjOpH?= =?Windows-1252?Q?WswCHJU74rKjjC//LNQav/wv9Fq0s9CRTansHLwGKMXQ9QKMdHfuSD0m?= =?Windows-1252?Q?/H2/7VxRdWRYBOdeIbYnbOyJtI/x4LNfKF+sVWJBSIYLcgsd4tgqyHSo?= =?Windows-1252?Q?wE3HQKew+j7ZsBZwcB7vksjEZxud6CGFQ/r3QbEVNRB0ucl9jLmXX9JS?= =?Windows-1252?Q?J2MYOYxobjed6UjKLx53AmhkO1b+957y/enPfG9UzQBrxKeOd6Rii1Zt?= =?Windows-1252?Q?Rxlo1iJFL6+urnduki/MQl4xOxcfj153TAWw4gTktQtJHHOfOF/4SdaQ?= =?Windows-1252?Q?HFS2pYyXiF3Th0vhOMKITsI4xRIB4nxz9ChjQLvGlPn5/7PR6D3Akeoy?= =?Windows-1252?Q?dEdUQKVPNzzuQw1bOwMPCJVfAwbcETo4Ryq7ZKYqoDVA7Pv+Z5tXVMK1?= =?Windows-1252?Q?NfNVnb9KroE+6HQTimly8xSgrIVluWMP2a1F8asrdqY0OcI0gNqKslSi?= =?Windows-1252?Q?rS5oFcuYEeX31y2yIqDhpWi/2fODes+IJN/fKSDADAHPKgaQXaGjPg/I?= =?Windows-1252?Q?l8mNm8P+g2hzkCNkLhFLRiJlpchwa+Y7rzoLjogtsnWEPtP4q4Qm/iyz?= =?Windows-1252?Q?ozU0p9cvxMf74JjNo4HT6aStwG6YBL4u4kWqhcLzQavXzHflcoqDFbTT?= =?Windows-1252?Q?OuvoDc+ngTNq2m7Q+OmPN1XhhLAATQUm3vPJ8HPPneV3To6T7kzMzBKy?= =?Windows-1252?Q?nPGJKZ4gjMop+fr+xCkDcZ2VBguFpjwMBoJP4WNRchMK3nPuyUz+hl5Q?= =?Windows-1252?Q?0TGpivv2T7nu6dlNg7C1sQjl2YOurEF2volovAWBgPqyVbFjEiJlzQ3k?= =?Windows-1252?Q?kVZTd6IyMOUKweKIWw6R++yqgzK517NjDg9oBbwsHsqJGPFrl5EWnnoF?= =?Windows-1252?Q?KZVCsKGSnIeJc/8YkFdzHDWULU8+xoXPxer+DTgYbyJraZP4wFNHdnvz?= =?Windows-1252?Q?YKHZib1QkD14phkQ/uSifvOiekJVbsalSyupMLTut4vY8gtG3oMN4C90?= =?Windows-1252?Q?h+pUKBg3ViJ3c9UGJ8tgKxUYmMSEK2dCwsox+PGWphJqyQzBbXoJ4avv?= =?Windows-1252?Q?kXV13321aQ2n6A38hfe5I+3hBWAal3PZZc/iM52nkYNy4vFpgj9UIxvw?= =?Windows-1252?Q?5GUutQIoZIlclBO8/ZnNvtI8InZRBImjsS7IKRlXqxJnJZLdpOa9GsCu?= =?Windows-1252?Q?znhd1IbTjqhxPH7Dfu6hTp5Za+0/uw+4EGePBDyaKt+yllnV1Bc7M2ll?= =?Windows-1252?Q?I2r6ZTYD+MNKE5OhpCJDr6yvJhrj/0zaiFlmPt1LMrqnUhQPpbOnxWrQ?= =?Windows-1252?Q?bP9IlT0l/AmtEBSYcQo9xsMwft/VB3yh30+/r/GGOYZ3AazA=3D=3D?= X-Microsoft-Exchange-Diagnostics: 1;AMSPR02MB119;5:hJL1SIpLTQJK5EMa+D97U0azXVzsgyllJDj3nQdQYnujgT2P421nh+bknKkX1nfVvAkey8ScP/PVS8xEUDnfgh8KMfQY5uiw5dUki4k9r8KtRZiTjqW151rF4H5Pgr0M3JKhzcMbgKGsv5vfFhzZGQ==;24:kFEszbjTkU54FzcEuKg0I6c+V9BU9TIyd1/L+IuXy8j0/HdqZYwfxSg4c3F2SG0tbAjAZYgrHqcgnxXMv82W+/11ed5tG08flS3bGSH906E= SpamDiagnosticOutput: 1:23 SpamDiagnosticMetadata: NSPM X-OriginatorOrg: ezchip.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Jan 2016 02:47:32.4193 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: AMSPR02MB119 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/25/2016 9:36 PM, Jeff Merkey wrote: > This patch adds an export which can be set by system debuggers to direct > the hard lockup and soft lockup detector to trigger an INT3 exception > and enter a debugger if one is active. It is assumed that if someone > sets this variable, then an int3 handler of some sort will be actively > loaded or registered via the notify die handler chain. > > This addition is extremely useful for debugging hard and soft lockups > real time and quickly from a console debugger. > > Signed-off-by: Jeff Merkey > --- > kernel/watchdog.c | 9 +++++++++ > 1 file changed, 9 insertions(+) Introducing Intel-specific assembly into generic code won't work. You would need to add a framework to allow platforms to specify a debugging instruction or maybe leverage some existing framework like arch_kgdb_breakpoint. -- Chris Metcalf, EZChip Semiconductor http://www.ezchip.com