From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754062AbcERUxH (ORCPT ); Wed, 18 May 2016 16:53:07 -0400 Received: from mail-bn1bon0090.outbound.protection.outlook.com ([157.56.111.90]:43840 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753479AbcERUxF (ORCPT ); Wed, 18 May 2016 16:53:05 -0400 Authentication-Results: vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=none action=none header.from=caviumnetworks.com; Subject: Re: [PATCH] tty: vt: Fix soft lockup in fbcon cursor blink timer. To: Scot Doyle , David Daney , Ming Lei , Dann Frazier References: <1463510464-28124-1-git-send-email-ddaney.cavm@gmail.com> <20160517204912.GA29719@amd> CC: Pavel Machek , Greg Kroah-Hartman , Jiri Slaby , Peter Hurley , David Airlie , , "Chintakuntla, Radha" , David Daney , Linux Kernel Mailing List , stable From: David Daney Message-ID: Date: Wed, 18 May 2016 13:38:23 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [50.233.148.158] X-ClientProxiedBy: SN1PR07CA0004.namprd07.prod.outlook.com (10.162.170.142) To BN4PR07MB2129.namprd07.prod.outlook.com (10.164.63.11) X-MS-Office365-Filtering-Correlation-Id: 62c844ed-c438-432b-010f-08d37f5c5dad X-Microsoft-Exchange-Diagnostics: 1;BN4PR07MB2129;2:Bm4mSTVZ9nPsPgrOTMN5y/fMOI0ZdLIu7vb+YX7kaYAwUINAbAFCkiyUDvn3QUm7UDWDH5w/86xgCtVc20+Srum5j/dA5E2zr/u7cOtNisbrmUMLzaNrRAziDNZp0VixQBcCb4RJYjFRjs/mqZfxIGuSnbgENWBQXv4xfyXdF1oj+dAvp1gD7BslrSVtogRn;3:629MCqedOP8vdOkrRZDpwYXpoDt2tVuYqdnOf5+e1SD8oMN9ne7P3AV4wBR9FoKbuR/po4luluU0VEI6lWVLoMU6SKAfVakHsB2kbjiaGpCmwaEBOMOvtpFnySKt2LC/;25:QF4zhtXJxuVO+vk4JKmMaBRn23jV76hBwlx0bzfHKoO1+2hLTG6FmABLVvpVPvg6yQbeHTMrYFQZeU3SpKPr3zf6sDt3W4nXrfBgNu9Orz4oXy+iZFM51DDyCdgddXWyuT3gB4OPAcFNfHYCiZeQdy6KMmFZZJ36CzutlWkbprVxPb16xxHCYpfWMDmQNy6Rrdr72/xD7K4Z6wXNpZVTurME6d6iQMzyKDi0CWW8m4SrwnWASibMV5yLBMFFVOKZBv6DFliZPVBlKhKCEZsaXy+iWJ8ADWQuNJcxLElSh8415nwrMZGn3pTgxR3ajQjOdprtzxHIyFftMqmKzVocHXmIFPl7cw7pyESkmgJF77O3CCXLQjCMQ2VR5VBzvs9LR3Xcov7zT7CKL38P4eYtpFE3mtCHba+VRByfySeto20= X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:BN4PR07MB2129; 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X-Microsoft-Exchange-Diagnostics: =?Windows-1252?Q?1;BN4PR07MB2129;23:4dW5JgVJlFXG1Z3RboJ8FMRKmxQqm1DGjzdHU?= =?Windows-1252?Q?NcKwSMndl4yb22JGwZXfiIQB8gx3p4QbwiZSoueDjmA6Ho632855EJx5?= =?Windows-1252?Q?oj+2w2z0S7nZUFPFAqaUsTyYlewYKrfENw43qCvFnGdkp5R5BHNHPLPS?= =?Windows-1252?Q?+zFlN5QajqgvCDKKI3OtFkzH264STTAlOcv/KQcm5D9C5O1OIn+ROMa6?= =?Windows-1252?Q?FVVEZXYkKYeX63LADIGOTzeD/s6ZSAf0oMxF7N1eMJQ/xO0xJseXRl23?= =?Windows-1252?Q?CO6PyJ0a+AcD9RT8VPZ5MNHw2pkaRK6oa3vChNDt5M8bELqcf3QAr9KF?= =?Windows-1252?Q?ySKLy3ql83Yj3cmxXPj32xGgPY5Sl0JVCLPKotpqMmvZ2NMJUiD58mkG?= =?Windows-1252?Q?l4JS2iQbqR6kgRPGfxprfEiM3yp2pH118KXPluC2n1MSezmPZJYoWa+H?= =?Windows-1252?Q?QAEcyzG9JHbSMFY/nIURdkc4HcE0WEqiyDR9y/p6+1WzmPb4+5X3pzw6?= =?Windows-1252?Q?EoC7rhI/LUIeG3V1QoD8cX1dySRo8SXS6jstF9Tia9aEYiz6AZMTMMFu?= =?Windows-1252?Q?/tp+BvEl963nVnKaCrHmUpWMub14Htq07W4twPJQjwUQQBJFMV4l+Iaz?= =?Windows-1252?Q?s22iEJ/hPmb4vHa4jxOK2sACeqUp8QY2queUc7GwDXFcEk+rFJnFSWwN?= =?Windows-1252?Q?TQOkkyXNikOnDf5M92+Ryia042RslDtaqPoARqXp89zyBVIUKqwb7r9T?= =?Windows-1252?Q?5NUfoY6wKCWdqwBdrvhI0atUtRAQ3szbqzp13iqau/izOZTOKVC96wiL?= =?Windows-1252?Q?2NRdrYHiCZcdrrHOwRtm9zpCnSHPEsly+G5bgJSjdM9oH5UAg955kK6B?= =?Windows-1252?Q?19ONGN/CHyHcJznBrBILcCTWJVZflG48Tr4VFggc6IALu1Rh9tTW1JSy?= =?Windows-1252?Q?mwNCh16VCLv+gFedAVwMAIuNUc9+gHegZbGmjvwpwYZuEnd6mz1vDbp1?= =?Windows-1252?Q?39szl3/QDxR/t2huyqOZAjWGNbGGjFRjM9AQbrHt3GO1IDLUG5mHumR6?= =?Windows-1252?Q?JGcm6kn1aYvhuPCE9H+LdzaWtQgKws9z8oXFwW61DNvXfcll9OlYIPb2?= =?Windows-1252?Q?+A89u3xkcd51Te9MOrT3+wGuMBtTjMu+ePdA9EYm0EUefzPF1lqBzKuZ?= =?Windows-1252?Q?9Uj4fjCEPW4ZFUYELNzkH5cYyQXUN/V9NyHmYz7jsFBaSQQWEq1?= X-Microsoft-Exchange-Diagnostics: 1;BN4PR07MB2129;5:kX8y4a+21K1VR6amXalikPjF44RrzPh523Se8yiqKDh9zZxKWz40hu7biTO9jb6ZWAs9TJWKKws8oiDEqjPbs9FzjYwL+MleBfpxunc2yVz72eK2EiY4Gw5SnKrCPMT3bBWbQcZZPGusuDKs+y3M5w==;24:Z14/RtPYW8+SV5pG+u4hexcO8mhrgxZ0g7+aVJWvQeDqaPvMfyOCqMuKUZ7QcShaadK0hSJ4b1mtFISc4ccfzU7rFRfMpK4P8QT/uCvd2jM=;7:7lVHxTBDdfmjcH58FcRlDjzQBKqdxWoNi9pnd4Jb5r2/BGMBbPznUj0+A1MkYuSzFVHazIZ1RrIcohpaEILXKIsMHcnLWf3v1cIe/SJqTpeIC3RKCiJ8vYqQZMefv28R/aI4SQ/AUgLT5wsnyACgDIAYNzerEF6lu7nytHq8nByFT4KFR2izd9tkG8yUTDe4 SpamDiagnosticOutput: 1:23 SpamDiagnosticMetadata: NSPM X-OriginatorOrg: caviumnetworks.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 May 2016 20:38:26.3303 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN4PR07MB2129 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/18/2016 01:24 PM, Scot Doyle wrote: > On Wed, 18 May 2016, Ming Lei wrote: >> On Wed, May 18, 2016 at 4:49 AM, Pavel Machek wrote: >>> On Tue 2016-05-17 11:41:04, David Daney wrote: >>>> From: David Daney >>>> >>>> We are getting somewhat random soft lockups with this signature: >>>> >>>> [ 86.992215] [] el1_irq+0xa0/0x10c >>>> [ 86.997082] [] cursor_timer_handler+0x30/0x54 >>>> [ 87.002991] [] call_timer_fn+0x54/0x1a8 >>>> [ 87.008378] [] run_timer_softirq+0x1c4/0x2bc >>>> [ 87.014200] [] __do_softirq+0x114/0x344 >>>> [ 87.019590] [] irq_exit+0x74/0x98 >>>> [ 87.024458] [] __handle_domain_irq+0x98/0xfc >>>> [ 87.030278] [] gic_handle_irq+0x94/0x190 >>>> >>>> This is caused by the vt visual_init() function calling into >>>> fbcon_init() with a vc_cur_blink_ms value of zero. This is a >>>> transient condition, as it is later set to a non-zero value. But, if >>>> the timer happens to expire while the blink rate is zero, it goes into >>>> an endless loop, and we get soft lockup. >>>> >>>> The fix is to initialize vc_cur_blink_ms before calling the con_init() >>>> function. >>>> >>>> Signed-off-by: David Daney >>>> Cc: stable@vger.kernel.org >>> >>> Acked-by: Pavel Machek >> >> Tested-by: Ming Lei >> >> Thanks David and Pavel for making it work! >> >>> >>> (And it is amazing how many problems configurable blink speed caused). >>> >>> Thanks! >>> Pavel >>> > > > Dann, Ming and David, thank you so much for all of your effort. > > There were three other reports in the past year, each leading to their own > patch, Why were none of the patches merged? Were they obviously incorrect, or is there some other problem that blocks the resolution of this issue? > of boot lockups occuring when the cursor flash timer was set using > an ops->cur_blink_jiffies value of 0. I plan to propose a patch within > the next day that will prevent this for all code paths. >