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From: Pavel Machek <pavel@ucw.cz>
To: David Daney <ddaney.cavm@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jslaby@suse.com>,
	Peter Hurley <peter@hurleysoftware.com>,
	Ming Lei <ming.lei@canonical.com>,
	Dann Frazier <dann.frazier@canonical.com>,
	Scot Doyle <lkml14@scotdoyle.com>,
	David Airlie <airlied@linux.ie>,
	dri-devel@lists.freedesktop.org,
	Radha.Chintakuntla@caviumnetworks.com,
	linux-kernel@vger.kernel.org,
	David Daney <david.daney@cavium.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH] tty: vt: Fix soft lockup in fbcon cursor blink timer.
Date: Tue, 17 May 2016 22:49:13 +0200	[thread overview]
Message-ID: <20160517204912.GA29719@amd> (raw)
In-Reply-To: <1463510464-28124-1-git-send-email-ddaney.cavm@gmail.com>

On Tue 2016-05-17 11:41:04, David Daney wrote:
> From: David Daney <david.daney@cavium.com>
> 
> We are getting somewhat random soft lockups with this signature:
> 
> [   86.992215] [<fffffc00080935e0>] el1_irq+0xa0/0x10c
> [   86.997082] [<fffffc000841822c>] cursor_timer_handler+0x30/0x54
> [   87.002991] [<fffffc000810ec44>] call_timer_fn+0x54/0x1a8
> [   87.008378] [<fffffc000810ef88>] run_timer_softirq+0x1c4/0x2bc
> [   87.014200] [<fffffc000809077c>] __do_softirq+0x114/0x344
> [   87.019590] [<fffffc00080af45c>] irq_exit+0x74/0x98
> [   87.024458] [<fffffc00080fac20>] __handle_domain_irq+0x98/0xfc
> [   87.030278] [<fffffc000809056c>] 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 <david.daney@cavium.com>
> Cc: stable@vger.kernel.org

Acked-by: Pavel Machek <pavel@ucw.cz>

(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

  reply	other threads:[~2016-05-17 20:49 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-17 18:41 [PATCH] tty: vt: Fix soft lockup in fbcon cursor blink timer David Daney
2016-05-17 20:49 ` Pavel Machek [this message]
2016-05-18  0:42   ` Ming Lei
2016-05-18 20:24     ` Scot Doyle
2016-05-18 20:38       ` David Daney
2016-05-19  4:21         ` [PATCH] fbcon: use default if cursor blink interval is not valid Scot Doyle
2016-05-19  7:25           ` Jeremy Kerr
2016-05-19  8:29           ` Ming Lei
2016-05-19  9:01           ` Pavel Machek
2016-05-19 14:22             ` Scot Doyle
2016-05-19 15:31               ` Ming Lei
2016-05-19 15:59           ` David Daney
2016-05-19 22:25             ` Scot Doyle
2016-05-19 22:31               ` [PATCH] fbcon: warn on invalid cursor blink intervals Scot Doyle
2016-05-19 22:50                 ` David Daney
2016-05-20  1:21                 ` Jeremy Kerr
2016-05-20  2:17                 ` Ming Lei
2016-05-20  2:26                   ` Jeremy Kerr
2016-05-20  2:48                     ` Ming Lei
2016-05-20  5:04                       ` Jeremy Kerr
2016-05-20 16:27                         ` Scot Doyle
2016-05-24  1:19                           ` Scot Doyle
2016-05-28 11:48                           ` Henrique de Moraes Holschuh
2016-06-12  5:05                             ` Chintakuntla, Radha
2016-05-28 11:45                 ` Henrique de Moraes Holschuh
2016-05-19  0:27       ` [PATCH] tty: vt: Fix soft lockup in fbcon cursor blink timer Ming Lei
2016-05-19  7:08         ` Pavel Machek
2016-05-19 22:35 ` Scot Doyle
2016-05-28 11:44 ` Henrique de Moraes Holschuh
2016-06-14 16:22 ` Ping: " David Daney

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