From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:47738 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755518AbcGYVl5 (ORCPT ); Mon, 25 Jul 2016 17:41:57 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Daney , Pavel Machek , Ming Lei , Scot Doyle , Henrique de Moraes Holschuh Subject: [PATCH 4.6 160/203] tty: vt: Fix soft lockup in fbcon cursor blink timer. Date: Mon, 25 Jul 2016 13:56:15 -0700 Message-Id: <20160725203435.923574318@linuxfoundation.org> In-Reply-To: <20160725203429.221747288@linuxfoundation.org> References: <20160725203429.221747288@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Daney commit 1b45996d2ebf9680ccd0db875fc668aa025f40fd upstream. 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 Acked-by: Pavel Machek Tested-by: Ming Lei Acked-by: Scot Doyle Tested-by: Henrique de Moraes Holschuh Signed-off-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -750,6 +750,7 @@ static void visual_init(struct vc_data * 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;