Commit 97c96c43 authored by David Daney's avatar David Daney Committed by Greg Kroah-Hartman

tty: vt: Fix soft lockup in fbcon cursor blink timer.

commit 1b45996d upstream.

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: default avatarDavid Daney <david.daney@cavium.com>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Tested-by: default avatarMing Lei <ming.lei@canonical.com>
Acked-by: default avatarScot Doyle <lkml14@scotdoyle.com>
Tested-by: default avatarHenrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 994b91f0
......@@ -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;
......
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