From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f196.google.com ([209.85.213.196]:36799 "EHLO mail-ig0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810AbcEQSlO (ORCPT ); Tue, 17 May 2016 14:41:14 -0400 From: David Daney To: 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 Cc: linux-kernel@vger.kernel.org, David Daney , stable@vger.kernel.org Subject: [PATCH] tty: vt: Fix soft lockup in fbcon cursor blink timer. Date: Tue, 17 May 2016 11:41:04 -0700 Message-Id: <1463510464-28124-1-git-send-email-ddaney.cavm@gmail.com> Sender: stable-owner@vger.kernel.org List-ID: 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 --- 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; -- 1.8.3.1