From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751839AbcEQUtS (ORCPT ); Tue, 17 May 2016 16:49:18 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:56382 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751191AbcEQUtR (ORCPT ); Tue, 17 May 2016 16:49:17 -0400 Date: Tue, 17 May 2016 22:49:13 +0200 From: Pavel Machek To: David Daney Cc: Greg Kroah-Hartman , Jiri Slaby , Peter Hurley , Ming Lei , Dann Frazier , Scot Doyle , David Airlie , dri-devel@lists.freedesktop.org, Radha.Chintakuntla@caviumnetworks.com, linux-kernel@vger.kernel.org, David Daney , stable@vger.kernel.org Subject: Re: [PATCH] tty: vt: Fix soft lockup in fbcon cursor blink timer. Message-ID: <20160517204912.GA29719@amd> References: <1463510464-28124-1-git-send-email-ddaney.cavm@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1463510464-28124-1-git-send-email-ddaney.cavm@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 (And it is amazing how many problems configurable blink speed caused). Thanks! Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html