From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out3-smtp.messagingengine.com ([66.111.4.27]:54101 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750730AbcE1LoP (ORCPT ); Sat, 28 May 2016 07:44:15 -0400 Date: Sat, 28 May 2016 08:44:10 -0300 From: Henrique de Moraes Holschuh 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, Pavel Machek , 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: <20160528114410.GA13329@khazad-dum.debian.net> 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> Sender: stable-owner@vger.kernel.org List-ID: On Tue, 17 May 2016, 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 Tested-by: Henrique de Moraes Holschuh on top of 4.4.11. > --- > drivers/tty/vt/vt.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c > index 3e3c757..eef5c36 100644 > --- a/drivers/tty/vt/vt.c > +++ b/drivers/tty/vt/vt.c > @@ -750,6 +750,7 @@ static void visual_init(struct vc_data *vc, int num, int init) > vc->vc_complement_mask = 0; > vc->vc_can_do_color = 0; > vc->vc_panic_force_write = false; > + vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS; > vc->vc_sw->con_init(vc, init); > if (!vc->vc_complement_mask) > vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800; -- "One disk to rule them all, One disk to find them. One disk to bring them all and in the darkness grind them. In the Land of Redmond where the shadows lie." -- The Silicon Valley Tarot Henrique Holschuh